Year	% female
1971	7.59757
1972	8.33548
1974	10.80041
1985	15.22626
1987	15.75295
1989	16.3818
1990	18.12703
1994	18.07754
1995	19.06659
1996	19.78372
1997	20.34393
1998	20.56319
1999	20.68748
2000	22.10113
2001	23.29231
2002	24.85567
2003	24.25176
2004	24.75599
2005	25.53468
2006	26.20987
2007	30.75524
2008	28.97094
2009	29.00713
2010	29.49234
2011	30.19792
2012	31.12869
2013	31.25439
2014	30.85782
2015	30.79583
2016	31.27065