Year	Percent
1990	0.22494
1991	0.22167
1992	0.21785
1993	0.2142
1994	0.21002
1995	0.37275
1996	0.36756
1997	0.36194
1998	0.3574
1999	0.35269
2000	0.3495
2001	0.31445
2002	0.38471
2003	0.3664
2005	0.367
2007	0.36614
2008	0.36181
2009	0.35768
2010	0.3499
2011	0.44015
2012	0.43432
2013	0.42338
2014	0.41817
2015	0.4205
2016	0.42256
2017	0.49179
2018	0.49368
2019	0.48672
2020	0.49214