Year	Percent
1982	19.3
1983	19.1
1990	36.87
1991	25.4
1992	34.3
1993	34.4
1996	37.1
1997	36
1998	37.7
1999	37.7
2000	36.5
2001	29.7
2002	28.3
2003	30.8
2004	32.2
2005	29.5
2006	27.5
2007	24.2
2008	24.5
2009	27.22
2010	28.92
2011	29.53
2012	28.54
2013	28.95
2016	22.39