Year	Percent
1983	2.77
1984	2.57
1985	2.05
1986	1.52
1987	2.31
1988	2.28
1989	2.11
1990	2.01
1991	1.58
1992	1.32
1993	1.29
1994	1.19
1995	1.01
1996	0.83
1997	0.9
1998	0.9
1999	0.93
2000	0.87
2001	0.75
2002	0.71
2003	0.73
2004	0.6
2005	0.59
2006	0.37
2007	0.6
2008	0.7
2009	0.82
2010	0.85
2011	0.63
2012	0.87
2013	0.74
2014	0.71
2015	0.67
2016	0.74
2017	0.63