Year	Percent
1991	47.585
1992	46.371
1993	46.047
1994	45.675
1995	45.42
1996	45.667
1997	47.06
1998	48.839
1999	49.473
2000	50.134
2001	50.756
2002	51.114
2003	50.703
2004	50.336
2005	50.507
2006	50.618
2007	50.69
2008	50.978
2009	50.021
2010	49.196
2011	47.489
2012	46.179
2013	45.27
2014	46.091
2015	46.925
2016	47.59
2017	48.327
2018	48.938
2019	49.06
2020	48.824
2021	48.575
2022	48.308