Year	Percent
1983	18.87
1984	13.96
1985	11.52
1986	8.14
1987	8.93
1988	8.54
1989	11.5
1990	11.53
1991	11.5
1992	12.34
1993	14.61
1994	10.18
1995	9.92
1996	10.59
1997	8.09
1998	7.17
1999	9.95
2000	6.72
2001	8.25
2002	7.07
2003	9.83
2004	7.79
2005	8.61
2006	7.68
2007	7.52
2008	9.52
2009	13.47
2010	15.6
2011	16.35
2012	15.81
2013	14.81
2014	14.23
2015	12.17
2016	12.18
2017	12.41
2018	10.54
2019	10.06
2020	11.61