Year	% of total
1970	86.93817128583954
1971	86.82252560330438
1972	86.66087805253481
1973	87.72251008669728
1974	87.7580422580856
1975	88.66608872571643
1976	88.4897609909546
1977	89.4016676645763
1978	88.77896877954122
1979	88.57364795598984
1980	88.05569016693299
1981	87.77381655228078
1982	87.64798162527889
1983	87.46929849741991
1984	88.0377175240381
1985	89.23011178019973
1986	89.17634009029932
1987	88.62958131550543
1988	88.34129681942319
1989	83.01055378077518
1990	100
1991	100
1992	100
1993	100
1994	100
1995	100
1996	100
1997	100
1998	100
1999	100
2000	100
2001	100
2002	100
2003	100
2004	100
2005	100
2006	100
2007	100
2008	100