Year	Years
1800	445.4
1950	137.3
1951	135.5
1952	132.4
1953	129.8
1963	81.6
1964	76.4
1965	71.5
1966	66.7
1967	62.3
1968	58.1
1969	54.2
1970	50.6
1971	47.5
1972	44.6
1973	42.1
1974	39.9
1975	37.9
1976	36
1977	34.3
1978	32.8
1979	31.4
1980	30.1
1981	29.1
1982	28.2
1983	27.4
1984	26.8
1985	26.2
1986	25.6
1987	25
1988	24.3
1989	23.6
1990	22.8
1991	22
1992	21.2
1993	20.6
1994	20.1
1995	19.6
1996	19.3
1997	19
1998	18.6
1999	18.3
2000	17.9
2001	17.5
2002	17
2003	16.5
2004	16
2005	15.6
2006	15.1
2007	14.7
2008	14.3
2009	13.8
2010	13.3
2011	12.9
2012	12.5
2013	12.1