Year	Percent
1983	23.76
1986	26.62
1987	27.61
1988	25
1989	18.59
1990	21.82
1991	29.69
1992	37.14
1995	33.33
1997	25.9
2003	24.11
2009	24.47
2010	26.74
2013	27.71
2014	29.63
2015	31.82
2016	27.85