Year	% female
1970	31.4358
1971	32.38177
1972	33.87318
1973	34.8687
1974	35.80459
1975	37.19556
1980	41.4604
1981	41.99775
1982	41.7505
1983	41.91612
1984	42.95298
1985	42.92949
1986	44.01394
1987	44.21726
1988	44.436
1999	48.6716
2000	48.53552
2001	48.22055
2002	48.66825
2003	50.3953
2004	48.07381
2005	48.62136
2006	48.08927
2007	46.45315
2008	47.60423
2009	47.26429