Year	Years
1800	426.2
1952	181.7
1953	178.4
1954	175.1
1955	171.9
1956	168.6
1957	165.5
1958	162.1
1959	158.5
1960	154.7
1961	150.7
1962	146.5
1963	141.9
1964	137.2
1965	132.5
1966	127.6
1967	122.8
1968	118
1969	113.2
1970	108.6
1971	104.2
1972	100
1973	95.8
1974	91.9
1975	88.2
1976	84.4
1977	80.4
1978	76.3
1979	71.9
1980	67.4
1981	62.8
1982	58.3
1983	53.9
1984	49.8
1985	46.1
1986	42.7
1987	39.7
1988	37.2
1989	35
1990	33.1
1991	31.4
1992	29.9
1993	28.7
1994	27.6
1995	26.7
1996	25.8
1997	25.1
1998	24.4
1999	23.7
2000	23.1
2001	22.4
2002	21.9
2003	21.4
2004	21.1
2005	20.7
2006	20.4
2007	20
2008	19.5
2009	19
2010	18.5
2011	18
2012	17.5
2013	16.9