Year	Percent
1991	53.808
1992	52.486
1993	50.509
1994	49.587
1995	48.907
1996	48.582
1997	49.095
1998	48.323
1999	46.772
2000	46.506
2001	45.118
2002	46.531
2003	46.886
2004	48.518
2005	49.804
2006	51.672
2007	52.115
2008	52.071
2009	49.103
2010	47.27
2011	49.127
2012	50.325
2013	50.825
2014	50.874
2015	52.556
2016	53.047
2017	53.375
2018	53.318
2019	53.206
2020	53.06
2021	52.89
2022	52.703