	Annual
1935	10.2
1936	10.2
1937	10.3
1938	10.3
1939	10.3
1940	10.4
1941	10.4
1942	10.7
1943	11.2
1944	11.6
1945	11.9
1946	12.5
1947	13.5
1948	14.4
1949	14.8
1950	15.1
1951	15.9
1952	16.7
1953	17.3
1954	17.8
1955	18.2
1956	18.9
1957	19.7
1958	20.6
1959	21.5
1960	22.3
1961	22.9
1962	23.5
1963	24.1
1964	24.6
1965	25.2
1966	26.3
1967	28.2
1968	29.9
1969	31.9
1970	34
1971	36.1
1972	37.3
1973	38.8
1974	42.4
1975	47.5
1976	52
1977	57
1978	61.8
1979	67.5
1980	74.9
1981	82.9
1982	92.5
1983	100.6
1984	106.8
1985	113.5
1986	122
1987	130.1
1988	138.6
1989	149.3
1990	162.8
1991	177
1992	190.1
1993	201.4
1994	211
1995	220.5
1996	228.2
1997	234.6
1998	242.1
1999	250.6
2000	260.8
2001	272.8
2002	285.6
2003	297.1
2004	310.1
2005	323.2
2006	336.2
2007	351.054
