Year	Percent
1990	0.6335
1991	0.50536
1992	0.45566
1993	0.44237
1994	0.45794
1995	0.64813
1996	0.66628
1997	0.65148
1998	0.63883
1999	0.61977
2000	0.61657
2001	0.60846
2002	0.61367
2003	0.60555
2004	0.58536
2005	0.58133
2006	0.59852
2007	0.59696
2008	0.59555
2009	0.56941
2010	0.57154
2011	0.5591
2012	0.55402
2013	0.55711
2014	0.5546
2015	0.54838
2016	0.54344
2017	0.53624
2018	0.5233
2019	0.49982
2020	0.53075