Year	% of total
1970	46.28377332247125
1971	43.80472897184838
1972	44.92823917899318
1973	41.80504194703195
1974	38.93680080378954
1975	37.181889609020416
1976	37.47938213827533
1977	37.68359337231977
1978	38.14477896411407
1979	38.186603547820084
1980	38.730346153238585
1981	40.122512509096424
1982	42.5470584408789
1983	36.42515482511751
1984	34.91221493731658
1985	37.133995538568435
1986	39.1804274270567
1987	40.7109720041324
1988	44.6764192619882
1989	45.77569808121583
1990	44.44444444444444
1991	44.44444444444444
1992	50
1993	50
1994	50
1995	50
1996	50
1997	50
1998	50
1999	50
2000	50
2001	50
2002	50
2003	50
2004	54.54545454545454
2005	54.54545454545454
2006	54.54545454545454
2007	54.54545454545454
2008	54.54545454545454