Year	% of total
1970	86.80214675613283
1971	86.7475770432572
1972	86.33618129957853
1973	86.1065852285178
1974	85.77328675990313
1975	85.70386739326469
1976	85.48709924295702
1977	85.1278095969646
1978	85.06780291659625
1979	84.97815144743882
1980	84.4845345113576
1981	84.08246724641067
1982	83.75434651147901
1983	83.273418540354
1984	80.98786967045895
1985	80.60014948164662
1986	80.9351621998319
1987	80.57275014934135
1988	80.27572304554211
1989	79.79620017783034
1990	96.68508287292818
1991	95.90643274853801
1992	95.45454545454545
1993	94.65648854961832
1994	93.7007874015748
1995	93.44262295081968
1996	92.10526315789474
1997	92.37288135593221
1998	90.65420560747664
1999	90.52631578947368
2000	90.52631578947368
2001	89.8989898989899
2002	88.67924528301887
2003	89.52380952380953
2004	89.28571428571429
2005	88.79310344827587
2006	89.92248062015504
2007	91.53846153846153
2008	92.51700680272108