Year	% female
1971	13.51351
1972	12.7185
1973	16.67691
1974	22.19042
1975	25.21326
1976	27.28571
1977	28.67955
1978	30.26671
1979	32.03005
1980	32.60815
1981	34.22928
1982	35.65302
1983	37.90102
1984	40.18187
1985	42.40604
1986	44.13628
1987	45.15538
1988	45.96919
1989	46.44265
1990	46.74865
1991	46.99968
1992	47.1511
1993	47.4518
1994	47.81988
1995	48.03725
1996	48.04038
1997	47.94922
1998	47.91813
1999	47.91401
2000	47.96693
2001	48.2131
2002	48.3484
2003	48.47834
2005	48.77499
2006	48.84834
2007	49.04129
2008	49.07582
2009	48.30104
2011	48.94936
2012	49.20543
2013	50.50137
2014	50.45752
2015	50.0465
2016	49.81026
2017	49.83997
2018	50.21005