Year	Percent
1991	51.062
1992	50.26
1993	49.463
1994	49.834
1995	49.767
1996	49.309
1997	48.862
1998	47.739
1999	46.722
2000	46.191
2001	46.31
2002	46.572
2003	46.126
2004	45.751
2005	45.799
2006	46.143
2007	46.526
2008	46.582
2009	45.685
2010	45.067
2011	45.532
2012	45.955
2013	46.762
2014	47.199
2015	48.296
2016	49.636
2017	50.099
2018	50.507
2019	50.39
2020	50.241
2021	50.039
2022	49.804