Year	Percent
1990	0.83824
1991	0.79683
1992	0.82938
1993	0.91639
1994	0.7973
1995	1.2594
1996	0.68818
1997	0.55107
1998	0.3824
1999	0.21717
2000	0.13999
2001	0.20157
2002	0.38319
2003	0.38472
2004	0.54174
2005	0.57054
2006	0.53174
2007	0.34231
2008	0.26069
2009	0.34608
2010	0.43886
2011	0.50547
2012	0.40594
2013	0.5362
2014	0.56921
2015	0.65518
2016	0.77514
2017	0.69014