Year	Percent
1990	0.85062
1991	0.8343
1992	0.81341
1993	0.78996
1994	0.76561
1995	0.85251
1996	0.8249
1997	0.79796
1998	0.77211
1999	0.78001
2000	0.75523
2001	0.79234
2002	0.76806
2003	0.74522
2004	0.55674
2005	0.54121
2007	0.51273
2008	0.49973
2009	0.58514
2010	0.57243
2011	0.56034
2012	0.54891
2013	0.53803
2014	0.52758
2015	0.51781
2016	0.50877
2017	0.4168
2018	0.52418
2019	0.416
2020	0.43365