Year	% of total
1970	74.23136580243222
1971	79.13378764842166
1972	55.59664615715513
1973	74.34441687888197
1974	83.13778997271292
1975	82.33014802405573
1976	73.1615783076933
1977	77.34964642066714
1978	81.67467696276509
1979	81.81058680281119
1980	81.43109056041632
1981	77.42816131255513
1982	77.42451537626363
1983	81.78427133546182
1984	77.5607169212075
1985	73.8362463034311
1986	67.05925432534225
1987	67.038024849099
1988	66.85477492321844
1989	66.60641571785182
1990	92.64069264069265
1991	92.51152073732719
1992	92.01817001946789
1993	92.23233030090972
1994	92.82544378698225
1995	91.87062937062937
1996	91.34808853118712
1997	90.77277970011534
1998	89.19667590027701
1999	89.86587183308494
2000	88.05513016845329
2001	89.35879945429741
2002	92.76595744680851
2003	89.47368421052632
2004	90.15706806282722
2005	89.91935483870968
2006	89.76958525345621
2007	87.32394366197182
2008	87.80971258671953