Year	Percent
1979	0.61
1980	0.57
1981	0.7
1982	0.56
1983	0.48
1984	0.34
2000	14.4
2001	15.73
2002	17.63
2003	16.36
2004	16.12
2005	16.47
2006	16.65
2012	13.59