Year	Total
1971	168.5
1972	168.8
1973	142.3
1974	177.6
1975	177.5
1976	177.7
1977	177.5
1978	176.6
1979	178.5
1980	177.6
1981	177.1
1982	159.9
1983	152.2
1984	154.6
1985	154.6
1986	152.7
1987	157.2
1988	156.6
1989	150.1
1990	142.8
1991	151
1992	167.1
1993	170.8
1994	184.9
1995	180.1
1996	189.5
1997	200.5
1998	192.8
1999	155.4
2000	167.2
2001	159.3
2002	191.2
2003	252.4
2004	233.7
2005	229.1
2006	200.4
2007	192.2
2008	165.8
2009	173.5