Year	Percent
1991	46.77
1992	47.186
1993	47.244
1994	47.484
1995	47.561
1996	46.924
1997	47.106
1998	47.238
1999	47.37
2000	47.489
2001	47.607
2002	47.713
2003	47.82
2004	47.953
2005	48.056
2006	48.169
2007	48.299
2008	48.412
2009	48.539
2010	48.703
2011	48.865
2012	49.037
2013	49.212
2014	49.375
2015	49.51
2016	49.784
2017	50
2018	50.133
2019	50.202
2020	50.2
2021	50.134
2022	50.01