Year	Percent
1984	11.02
1985	11.51
1986	12.46
1989	15.44
1991	12.97
1996	9.57
2000	10.26
2003	13.68
2005	14.52
2006	14.52
2010	17.63
2013	20.79
2016	20.46
2017	20.42