Quick function to adjust for inflation

adjustForInflation.js

var adjustForInflation = function(amount, yearFrom, yearTo) {
    // Annual average CPI-U figures from BLS:
    // http://www.bls.gov/cpi/cpifiles/cpiai.txt
    // 
    // If you want the current year as well, BLS' inflation calculator suggests
    // using the most recent monthly index value since there won't be an annual
    // average available yet: http://www.bls.gov/cpi/cpicalc.htm
    var cpi = {
        1913: 9.9, 1914: 10.0, 1915: 10.1, 1916: 10.9, 1917: 12.8, 1918: 15.1,
        1919: 17.3, 1920: 20.0, 1921: 17.9, 1922: 16.8, 1923: 17.1, 1924: 17.1,
        1925: 17.5, 1926: 17.7, 1927: 17.4, 1928: 17.1, 1929: 17.1, 1930: 16.7,
        1931: 15.2, 1932: 13.7, 1933: 13.0, 1934: 13.4, 1935: 13.7, 1936: 13.9,
        1937: 14.4, 1938: 14.1, 1939: 13.9, 1940: 14.0, 1941: 14.7, 1942: 16.3,
        1943: 17.3, 1944: 17.6, 1945: 18.0, 1946: 19.5, 1947: 22.3, 1948: 24.1,
        1949: 23.8, 1950: 24.1, 1951: 26.0, 1952: 26.5, 1953: 26.7, 1954: 26.9,
        1955: 26.8, 1956: 27.2, 1957: 28.1, 1958: 28.9, 1959: 29.1, 1960: 29.6,
        1961: 29.9, 1962: 30.2, 1963: 30.6, 1964: 31.0, 1965: 31.5, 1966: 32.4,
        1967: 33.4, 1968: 34.8, 1969: 36.7, 1970: 38.8, 1971: 40.5, 1972: 41.8,
        1973: 44.4, 1974: 49.3, 1975: 53.8, 1976: 56.9, 1977: 60.6, 1978: 65.2,
        1979: 72.6, 1980: 82.4, 1981: 90.9, 1982: 96.5, 1983: 99.6,
        1984: 103.9, 1985: 107.6, 1986: 109.6, 1987: 113.6, 1988: 118.3,
        1989: 124.0, 1990: 130.7, 1991: 136.2, 1992: 140.3, 1993: 144.5,
        1994: 148.2, 1995: 152.4, 1996: 156.9, 1997: 160.5, 1998: 163.0,
        1999: 166.6, 2000: 172.2, 2001: 177.1, 2002: 179.9, 2003: 184.0,
        2004: 188.9, 2005: 195.3, 2006: 201.6, 2007: 207.342, 2008: 215.303,
        2009: 214.537, 2010: 218.056, 2011: 224.939, 2012: 229.594,
        2013: 232.957
    };
    
    return amount * cpi[yearTo] / cpi[yearFrom];
};