Year	% of total
1970	40.46458739170692
1971	45.32547369019206
1972	44.932219510494384
1973	44.25322701020865
1974	45.763251585585465
1975	44.52797403057658
1976	46.05299087204547
1977	44.581570396062624
1978	43.917855868579494
1979	41.365719286326176
1980	42.80975152489071
1981	44.27965024734847
1982	43.325343394462045
1983	43.28462026518421
1984	45.92731100959179
1985	46.452135212113035
1986	48.69631906719587
1987	45.91938092414655
1988	51.039047278077796
1989	50.60373287991181
1990	94.73684210526315
1991	95.39473684210526
1992	95.39473684210526
1993	95.39473684210526
1994	94.77124183006535
1995	95.39473684210526
1996	92.13483146067416
1997	92.3076923076923
1998	92.5531914893617
1999	92.5531914893617
2000	91.56626506024097
2001	92.04545454545455
2002	94.64285714285714
2003	96.15384615384616
2004	95.73170731707317
2005	96.23655913978494
2006	96.29629629629629
2007	95.40229885057471
2008	95.42857142857143