Year	Percent
1991	50.174
1992	50.58
1993	50.871
1994	50.939
1995	51.165
1996	51.466
1997	51.654
1998	51.797
1999	52.018
2000	52.099
2001	52.157
2002	52.359
2003	52.362
2004	52.3
2005	52.294
2006	52.446
2007	52.333
2008	52.161
2009	51.897
2010	51.474
2011	51.485
2012	51.119
2013	50.856
2014	50.478
2015	50.129
2016	49.818
2017	49.675
2018	49.582
2019	49.501
2020	49.424
2021	49.35
2022	49.273