Year	% of total
1970	69.81076380363078
1971	70.2665041222399
1972	68.25217372827335
1973	68.70053042969404
1974	66.71368136968404
1975	63.75994477985898
1976	66.3209627663682
1977	66.85663048174759
1978	67.63613370309646
1979	68.67265033978714
1980	66.61175669589822
1981	65.38857069776606
1982	64.4723175691759
1983	62.94813310959652
1984	60.99806398275375
1985	59.74345517434115
1986	56.723848205625615
1987	55.63016739732477
1988	53.228095032459066
1989	53.6108858512338
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