Year	Percent
1983	30.56
1986	35.44
1987	36.49
1988	32.54
1989	25.53
1990	30.67
1991	33.46
1992	42.19
1995	37.77
1997	30.04
2003	26.21
2009	24.4
2010	26.06
2013	29.61
2014	33.77
2015	29.26
2016	26.67
2017	26.54
2018	24.62
2019	26.03