Year	Percent
1990	0.65186
1991	0.58484
1992	0.53451
1993	0.56535
1994	0.72509
1995	0.83608
1996	0.96295
1997	1.04159
1998	1.10423
1999	1.47057
2000	1.67652
2001	1.61097
2002	1.80062
2003	1.92642
2004	1.73411
2005	1.57416
2006	1.47824
2007	1.31908
2008	1.3668
2009	1.66915
2010	1.98794
2011	1.71866
2012	1.67234
2013	1.59445
2014	1.37311
2015	1.26348
2016	1.20191
2017	1.02801