Year	% of total
1970	95.93984273938688
1971	95.75503970245896
1972	95.69751731736041
1973	95.49946668669722
1974	95.27681364445574
1975	95.20222591799451
1976	95.11126307448494
1977	95.14686424164206
1978	95.20838157420236
1979	95.52949385498779
1980	95.6572620547696
1981	95.71435488788326
1982	95.47236574254308
1983	95.45923466665865
1984	94.84413008177658
1985	94.64017887376657
1986	94.75200208008317
1987	94.71264421582413
1988	94.41020159555292
1989	94.03965754465749
1990	97.33155436957972
1991	97.35413839891451
1992	97.18599862731641
1993	97.16459197786999
1994	97.18120805369126
1995	97.18770438194899
1996	97.16790289952797
1997	97.08672086720867
1998	97.02009702009701
1999	97.03304113283883
2000	96.7479674796748
2001	96.9758064516129
2002	96.99680511182109
2003	96.92597239648683
2004	96.71484888304862
2005	96.74267100977198
2006	96.77206851119895
2007	96.81697612732096
2008	96.63923182441701