Year	Percent
1986	4.79
1987	4.47
1988	4.05
1989	3.56
1990	2.86
1991	3.76
1992	1.71
1993	1.79
1994	2.07
1995	1.97
1996	1.6
1997	1.48
1998	2.25
1999	2
2000	2.25
2001	2.27
2002	1.83
2003	1.55
2004	1.44
2005	1.45
2006	1.21
2007	1.06
2008	0.91
2009	0.86
2010	0.94
2011	0.61
2012	0.66
2013	0.67
2014	0.53
2015	0.51
2016	0.63
2017	0.46