Year	Percent
1975	9.84
1976	9.92
1980	12.1
1981	9.8
1982	10.8
1983	9.11
1986	7.17
1992	3.7072
2002	9.7
2004	7.7
2005	7.7
2006	7.5
2007	9.9
2009	9.8
2011	15.7
2012	10.8