Year	Percent
1991	46.049
1992	45.897
1993	45.814
1994	46.751
1995	47.504
1996	48.201
1997	48.831
1998	44.595
1999	45.352
2000	47.053
2001	47.667
2002	48.441
2003	47.455
2004	48.408
2005	48.691
2006	49.114
2007	49.19
2008	48.877
2009	47.751
2010	47.844
2011	48.152
2012	48.537
2013	48.859
2014	49.641
2015	50.066
2016	50.351
2017	50.345
2018	50.316
2019	50.288
2020	50.17
2021	50.009
2022	49.79