Year	% (national estimate)
1979	26.59
1989	41.19
1991	60.1
1992	58.8
1993	60.2
1994	61.04
1995	61.3
1996	58.2
1997	62.5
1998	60.26
1999	63.5
2001	66.1
2002	65.1
2008	69
2009	59.4
2011	59.6
2012	59.42