Year	Percent
1991	48.685
1992	49.121
1993	49.284
1994	49.63
1995	49.804
1996	49.245
1997	49.488
1998	49.753
1999	49.922
2000	50.069
2001	50.174
2002	50.253
2003	50.331
2004	50.386
2005	50.433
2006	50.476
2007	50.524
2008	50.605
2009	50.627
2010	50.76
2011	50.941
2012	51.09
2013	51.251
2014	51.376
2015	51.422
2016	51.461
2017	51.426
2018	51.342
2019	51.234
2020	51.108
2021	50.973
2022	50.845