1764	276.7
1791	279.7
1816	283.8
1839	283.1
1843	287.4
1847	286.8
1854	288.2
1869	289.3
1874	289.5
1878	290.3
1887	292.3
1899	295.8
1903	294.8
1905	296.9
1909	299.2
1915	300.5
1921	301.6
1927	305.5
1935	306.6
1943	307.9
1953	312.7
1959	315.8
1960	316.8
1961	317.5
1962	318.3
1963	318.8
1964	318.5
1965	319.9
1966	321.2
1967	322
1968	322.8
1969	323.9
1970	325.3
1971	326.2
1972	327.3
1973	329.5
1974	330.1
1975	331
1976	332
1977	333.7
1978	335.3
1979	336.7
1980	338.5
1981	339.8
1982	341
1983	342.6
1984	344.3
1985	345.7
1986	347
1987	348.8
1988	351.4
1989	352.7
1990	354
1991	355.5
1992	356.2
1993	357
1994	358.8
1995	360.7