Year	Total
1971	277
1972	280.2
1973	250.9
1974	266.6
1975	253.6
1976	254.4
1977	233.9
1978	253
1979	222
1980	223.9
1981	224.3
1982	247.1
1983	235.1
1984	272.5
1985	252.2
1986	255.4
1987	256.1
1988	260.2
1989	309.6
1990	484.6
1991	485.3
1992	484.4
1993	472.6
1994	485.4
1995	483.4
1996	497.6
1997	510.3
1998	466.7
1999	481.3
2000	588.9
2001	500.3
2002	393.3
2003	396.1
2004	412.2
2005	411.6
2006	411.2
2007	412.4
2008	493.7
2009	530.9