Year	% female
1970	30.40595
1971	30.22833
1972	30.18512
1973	31.51811
1974	31.39201
1975	30.82121
1976	30.69759
1977	30.23797
1978	30.14646
1979	30.34484
1980	30.12093
1981	30.87967
1982	32.9665
1983	30.88522
1984	28.29425
1985	30.87016
1986	33.16441
1987	35.00395
1988	36.34602
1989	37.26735
1990	36.99829
1991	36.72811
1992	36.86197
1993	36.34878
1994	34.99407
1995	34.82074
1996	34.86217
1997	34.7132
1998	34.85718
1999	34.82197
2000	35.26138
2001	35.34872
2002	35.69914
2003	35.90769
2004	36.51473
2005	36.81922
2006	37.99989
2007	38.37065
2008	38.45812
2009	38.41512
2010	37.85068
2011	37.83212
2012	38.29515
2013	39.0448
2014	40.02954
2015	41.30866
2016	41.48323
2017	41.08609
2018	40.89686