Year	Percent
1983	3.09
1984	2.61
1985	2.44
1986	1.88
1987	1.97
1988	1.74
1989	1.71
1990	1.7
1991	1.57
1992	1.1
1993	1.44
1994	1.16
1995	1.31
1996	0.76
1997	0.68
1998	0.56
1999	0.72
2000	0.55
2001	0.56
2002	0.56
2003	0.18
2004	0.33
2005	0.27
2006	0.2
2007	0.17
2008	0.22
2009	0.65
2010	0.43
2011	0.44
2012	0.47
2013	0.4
2014	0.48
2015	0.81
2016	0.83
2017	0.72