Year	% of total
1970	95.07608634094642
1971	94.77688816119395
1972	94.87823963129786
1973	95.78341688290567
1974	95.92081690797313
1975	96.63584712397171
1976	96.99203905115927
1977	97.21027633017042
1978	97.70339746630188
1979	97.64155398435275
1980	97.22983982408289
1981	96.82129112681667
1982	96.55237264689961
1983	96.21196266093874
1984	96.12259605761454
1985	97.52539980317871
1986	97.71406645589748
1987	97.36699554223102
1988	97.23173776996619
1989	96.95062565625166
1990	40
1991	40
1992	40
1993	40
1994	40
1995	40
1996	40
1997	40
1998	40
1999	40
2000	40
2001	40
2002	40
2003	40
2004	40
2005	40
2006	40
2007	40
2008	40