Year	Percent
1983	7.93
1984	10.21
1985	10.33
1986	10.57
1987	12.15
1988	11.82
1989	11.18
1990	9.5
1991	9.41
1992	8.36
1993	8.21
1994	8.42
1995	7.74
1996	6.77
1997	6.16
1998	5.05
1999	4.26
2000	2.53
2001	2.64
2002	2.37
2003	2.37
2004	2.42
2005	2.79
2006	2.42
2007	2.47
2008	3.43
2009	6.59
2010	8.77
2011	9.72
2012	10.67
2013	10.82
2014	9.65
2015	7.9
2016	6.51
2017	5.83
2018	4.62
2019	3.6
2020	4.05