Year	Percent
1982	60.29
1983	62.91
1984	62.88
1985	35
1988	31.54
1989	30.8
1990	32.43
1991	32.05
1992	33.78
1993	35.21
1994	33.8
1995	34.35
1996	34.27
1997	35.13
1998	35.85
1999	35.81
2006	49.17
2007	49.77
2009	51.75
2010	50.07
2011	49.38
2012	50.42
2013	50.69
2014	51.06
2015	52.37
2016	53.72
2017	54.08