Year	% of female population ages 15+ (national estimate)
1960	20
1970	23.72
1976	26.85
1977	27.71
1978	27.84
1979	27.86
1980	28.09
1981	28.47
1982	28.31
1983	26.77
1984	26.82
1985	28.16
1986	28.11
1987	29.27
1988	31.7
1990	30.91
1991	31.22
1992	32.11
1993	34.2
1995	33.66
1996	34.25
1997	35.17
1998	35.12
1999	36.67
2000	34.9
2002	36.26
2003	37.01
2004	36.56
2005	37.87
2006	38.24
2007	37.09
2008	36.5
2010	34.1
2011	33.3
2012	33.5
2015	31.93