Year	Years
1800	497.9
1900	472.6
1931	296.2
1950	194
1951	191.9
1952	187.4
1953	183.5
1954	179.4
1955	174.4
1956	170
1957	165.4
1958	160.7
1959	156.1
1960	150.8
1961	146.3
1962	141.9
1963	136.9
1964	132.7
1965	128.4
1966	124.2
1967	120.1
1977	138.3
1978	133.5
1979	128.8
1980	124.2
1981	119.7
1982	115.3
1983	111.3
1984	107.4
1985	103.6
1986	100.1
1987	96.9
1988	94.2
1989	92.1
1990	90.7
1991	90
1992	89.8
1993	89.9
1994	89.9
1995	89.7
1996	88.9
1997	87.8
1998	86.2
1999	84.3
2000	81.9
2001	79.6
2002	77.4
2003	75.2
2004	73.1
2005	71
2006	68.9
2007	66.8
2008	64.7
2009	62.8
2010	61
2011	59
2012	57
2013	55.2