{
  "table": "inflation-calculator-indices",
  "schema": 1,
  "version": "2026-11-11.1",
  "title": "Consumer price indices for comparing money across years: France (INSEE franc-euro converter coefficients, 1901-2025) and the United Kingdom (ONS CPI annual averages, 1988-2025), with the euro-franc conversion rate and the projection presets",
  "doc": "Rule table read by the inflation-calculator handlers (ctx.data['inflation-calculator-indices']). France: the series INSEE publishes for its franc-euro purchasing-power converter, 'Coefficient de transformation de l'euro ou du franc d'une année, en euro ou en franc d'une autre année - Base 2025' (idbank 011813530), one figure per calendar year, base 2025 = 100, two decimals; from 1993 it is the annual average consumer price index (all households; mainland France until 1998, France including the overseas departments from 1999), and from 1901 to 1992 the index for urban households headed by a manual or office worker. These are the exact figures the converter on insee.fr uses (embedded in its page as convertRates on 2026-11-11), so the results match it to the cent (apart from rare results that fall exactly on a half-cent, which the converter's floating-point arithmetic can round down). Before 1945 a coefficient has one or two significant digits (0.03 for 1901), so results that involve those years are approximate only (a coefficient of 0.03 may stand for anything from 0.025 to 0.035). United Kingdom: the ONS Consumer Prices Index, all items, 2015 = 100 (CDID D7BT, dataset MM23), calendar-year averages as published to one decimal place; the series starts in 1988 and covers the whole United Kingdom. Index values are final (neither series is revised, apart from INSEE re-basing its coefficients each year when it adds a year). The table as a whole is valid until the day before the first publication of the 2026 annual averages (INSEE and the ONS are expected to publish the December 2026 indices around mid-January 2027): 2026 then has to be added, and INSEE's coefficients re-read, because INSEE re-bases them on the new year. Currencies: francs_per_unit is the number of (new) French francs in one unit of the currency; 1 euro = 6.55957 francs is the irrevocable rate of Council Regulation (EC) No 2866/98; 1 new franc = 100 old francs from 1 January 1960. Presets: the rates offered for a projection; rate is in percentage points. Every value carries source_url (primary official source), source_date (that source's own date), retrieved (the day it was read there), valid_from and valid_until (null: in force until changed; a null valid_from means the start date was not verified for this table).",
  "reviewed_on": "2026-11-11",
  "reviewed_by": "apps agent (inflation-calculator): every figure read at its official source on 2026-11-11 (INSEE BDM SDMX series 011813530, 011814639 and 011814640 and the converter page; ONS MM23 series D7BT and D7G7; EUR-Lex 31998R2866; the ECB strategy page; the Bank of England inflation pages); owner review pending",
  "valid_from": "2026-11-11",
  "valid_until": "2027-01-14",
  "locale_country": {
    "fr-FR": "FR",
    "en-GB": "GB"
  },
  "countries": {
    "FR": {
      "currency": "EUR",
      "index": {
        "series": "011813530",
        "name": {
          "fr-FR": "coefficient de transformation de l’euro ou du franc (Insee, base 2025)",
          "en-GB": "INSEE euro and franc conversion coefficient (base 2025)"
        },
        "short": {
          "fr-FR": "indice Insee",
          "en-GB": "INSEE index"
        },
        "base": "2025 = 100",
        "decimals": 2,
        "rough_below": 1,
        "first_year": 1901,
        "last_year": 2025,
        "values": {"1901": 0.03, "1902": 0.03, "1903": 0.03, "1904": 0.03, "1905": 0.03, "1906": 0.03, "1907": 0.03, "1908": 0.03, "1909": 0.03, "1910": 0.03, "1911": 0.04, "1912": 0.04, "1913": 0.04, "1914": 0.04, "1915": 0.04, "1916": 0.05, "1917": 0.06, "1918": 0.07, "1919": 0.1, "1920": 0.13, "1921": 0.12, "1922": 0.12, "1923": 0.12, "1924": 0.14, "1925": 0.15, "1926": 0.2, "1927": 0.21, "1928": 0.21, "1929": 0.21, "1930": 0.22, "1931": 0.21, "1932": 0.19, "1933": 0.18, "1934": 0.18, "1935": 0.17, "1936": 0.17, "1937": 0.22, "1938": 0.25, "1939": 0.26, "1940": 0.31, "1941": 0.37, "1942": 0.45, "1943": 0.55, "1944": 0.68, "1945": 1, "1946": 1.53, "1947": 2.29, "1948": 3.63, "1949": 4.11, "1950": 4.52, "1951": 5.25, "1952": 5.88, "1953": 5.78, "1954": 5.8, "1955": 5.86, "1956": 6.1, "1957": 6.29, "1958": 7.23, "1959": 7.68, "1960": 7.96, "1961": 8.23, "1962": 8.62, "1963": 9.03, "1964": 9.34, "1965": 9.57, "1966": 9.83, "1967": 10.1, "1968": 10.56, "1969": 11.24, "1970": 11.82, "1971": 12.49, "1972": 13.26, "1973": 14.49, "1974": 16.48, "1975": 18.41, "1976": 20.19, "1977": 22.08, "1978": 24.08, "1979": 26.67, "1980": 30.28, "1981": 34.34, "1982": 38.4, "1983": 42.1, "1984": 45.22, "1985": 47.85, "1986": 49.12, "1987": 50.67, "1988": 52.03, "1989": 53.91, "1990": 55.72, "1991": 57.54, "1992": 58.87, "1993": 60.11, "1994": 61.1, "1995": 62.26, "1996": 63.46, "1997": 64.23, "1998": 64.65, "1999": 65, "2000": 66.08, "2001": 67.16, "2002": 68.46, "2003": 69.89, "2004": 71.39, "2005": 72.64, "2006": 73.85, "2007": 74.95, "2008": 77.06, "2009": 77.13, "2010": 78.31, "2011": 79.96, "2012": 81.52, "2013": 82.23, "2014": 82.65, "2015": 82.68, "2016": 82.83, "2017": 83.68, "2018": 85.23, "2019": 86.18, "2020": 86.59, "2021": 88.01, "2022": 92.61, "2023": 97.12, "2024": 99.07, "2025": 100},
        "source_url": "https://www.insee.fr/fr/statistiques/serie/011813530",
        "data_url": "https://bdm.insee.fr/series/sdmx/data/SERIES_BDM/011813530",
        "method_url": "https://www.insee.fr/fr/information/2417794",
        "source_date": "2026-02-05",
        "retrieved": "2026-11-11",
        "valid_from": "2026-02-05",
        "valid_until": "2027-01-14"
      },
      "currencies": [
        {
          "code": "EUR",
          "francs_per_unit": "6.55957",
          "first_year": 1999,
          "name": {
            "fr-FR": "euros",
            "en-GB": "euros"
          },
          "legal_basis": "Council Regulation (EC) No 2866/98 of 31 December 1998, article 1",
          "source_url": "https://eur-lex.europa.eu/legal-content/FR/TXT/?uri=CELEX:31998R2866",
          "source_date": "1998-12-31",
          "retrieved": "2026-11-11",
          "valid_from": "1999-01-01",
          "valid_until": null
        },
        {
          "code": "FRF",
          "francs_per_unit": "1",
          "last_year": 2001,
          "name": {
            "fr-FR": "francs",
            "en-GB": "French francs"
          },
          "note": "last_year: the last calendar year in which prices were in francs; INSEE: 1 euro = 6.55957 francs en 2002, and the euro was an accounting currency only from 1 January 1999 (first_year of EUR, the date Regulation 2866/98 entered into force, article 2).",
          "source_url": "https://www.insee.fr/fr/information/2417794",
          "source_date": "2026-11-11",
          "retrieved": "2026-11-11",
          "valid_from": "1960-01-01",
          "valid_until": null
        }
      ],
      "old_franc": {
        "per_franc": 100,
        "since": "1960-01-01",
        "rule": {
          "fr-FR": "1 franc = 100 anciens francs depuis le 1er janvier 1960",
          "en-GB": "1 new franc = 100 old francs from 1 January 1960"
        },
        "source_url": "https://www.insee.fr/fr/information/2417794",
        "source_date": "2026-11-11",
        "retrieved": "2026-11-11",
        "valid_from": "1960-01-01",
        "valid_until": null
      },
      "presets": [
        {
          "id": "fr-target",
          "rate": 2,
          "name": {
            "fr-FR": "Objectif de la BCE",
            "en-GB": "ECB target"
          },
          "note": {
            "fr-FR": "La BCE vise une inflation de 2 % à moyen terme, un objectif symétrique.",
            "en-GB": "The ECB aims for 2% inflation over the medium term, a symmetric target."
          },
          "source_url": "https://www.ecb.europa.eu/mopo/strategy/html/index.fr.html",
          "source_date": "2026-11-11",
          "retrieved": "2026-11-11",
          "valid_from": null,
          "valid_until": null
        },
        {
          "id": "fr-last-year",
          "rate": 0.9,
          "name": {
            "fr-FR": "Inflation de 2025",
            "en-GB": "Inflation in 2025"
          },
          "note": {
            "fr-FR": "Hausse des prix à la consommation en moyenne annuelle en 2025 (Insee).",
            "en-GB": "Annual average rise in consumer prices in 2025 (INSEE)."
          },
          "series": "011814640",
          "source_url": "https://www.insee.fr/fr/statistiques/serie/011814640",
          "data_url": "https://bdm.insee.fr/series/sdmx/data/SERIES_BDM/011814640",
          "source_date": "2026-02-27",
          "retrieved": "2026-11-11",
          "valid_from": "2026-02-27",
          "valid_until": "2027-01-14"
        }
      ]
    },
    "GB": {
      "currency": "GBP",
      "index": {
        "series": "D7BT",
        "name": {
          "fr-FR": "indice des prix à la consommation CPI (ONS, base 2015)",
          "en-GB": "ONS Consumer Prices Index, CPI (2015 = 100)"
        },
        "short": {
          "fr-FR": "CPI",
          "en-GB": "CPI"
        },
        "base": "2015 = 100",
        "decimals": 1,
        "rough_below": 0,
        "first_year": 1988,
        "last_year": 2025,
        "values": {"1988": 49.6, "1989": 52.2, "1990": 55.9, "1991": 60.1, "1992": 62.6, "1993": 64.2, "1994": 65.5, "1995": 67.2, "1996": 68.8, "1997": 70.1, "1998": 71.2, "1999": 72.1, "2000": 72.7, "2001": 73.6, "2002": 74.5, "2003": 75.5, "2004": 76.5, "2005": 78.1, "2006": 79.9, "2007": 81.8, "2008": 84.7, "2009": 86.6, "2010": 89.4, "2011": 93.4, "2012": 96.1, "2013": 98.5, "2014": 100, "2015": 100, "2016": 100.7, "2017": 103.4, "2018": 105.9, "2019": 107.8, "2020": 108.7, "2021": 111.6, "2022": 121.7, "2023": 130.5, "2024": 133.9, "2025": 138.4},
        "source_url": "https://www.ons.gov.uk/economy/inflationandpriceindices/timeseries/d7bt/mm23",
        "data_url": "https://www.ons.gov.uk/generator?format=csv&uri=/economy/inflationandpriceindices/timeseries/d7bt/mm23",
        "method_url": "https://www.bankofengland.co.uk/monetary-policy/inflation/inflation-calculator",
        "source_date": "2026-10-21",
        "retrieved": "2026-11-11",
        "valid_from": "2026-10-21",
        "valid_until": "2027-01-14"
      },
      "currencies": [
        {
          "code": "GBP",
          "francs_per_unit": null,
          "name": {
            "fr-FR": "livres sterling",
            "en-GB": "pounds"
          },
          "source_url": "https://www.ons.gov.uk/economy/inflationandpriceindices/timeseries/d7bt/mm23",
          "source_date": "2026-10-21",
          "retrieved": "2026-11-11",
          "valid_from": null,
          "valid_until": null
        }
      ],
      "presets": [
        {
          "id": "gb-target",
          "rate": 2,
          "name": {
            "fr-FR": "Objectif de la Banque d’Angleterre",
            "en-GB": "Bank of England target"
          },
          "note": {
            "fr-FR": "Le gouvernement britannique fixe à la Banque d’Angleterre un objectif d’inflation CPI de 2 %.",
            "en-GB": "The Government sets the Bank of England a 2% target for CPI inflation."
          },
          "source_url": "https://www.bankofengland.co.uk/monetary-policy/inflation",
          "source_date": "2026-10-21",
          "retrieved": "2026-11-11",
          "valid_from": null,
          "valid_until": null
        },
        {
          "id": "gb-last-year",
          "rate": 3.4,
          "name": {
            "fr-FR": "Inflation CPI de 2025",
            "en-GB": "CPI inflation in 2025"
          },
          "note": {
            "fr-FR": "Taux annuel CPI de 2025 publié par l’ONS.",
            "en-GB": "The CPI annual rate for 2025 published by the ONS."
          },
          "series": "D7G7",
          "source_url": "https://www.ons.gov.uk/economy/inflationandpriceindices/timeseries/d7g7/mm23",
          "data_url": "https://www.ons.gov.uk/generator?format=csv&uri=/economy/inflationandpriceindices/timeseries/d7g7/mm23",
          "source_date": "2026-10-21",
          "retrieved": "2026-11-11",
          "valid_from": null,
          "valid_until": "2027-01-14"
        }
      ]
    }
  }
}