Year	Percent
1991	49.604
1992	49.837
1993	49.988
1994	50.02
1995	49.817
1996	50.066
1997	50.199
1998	50.21
1999	50.101
2000	49.926
2001	49.995
2002	49.969
2003	49.901
2004	49.757
2005	49.578
2006	49.521
2007	49.36
2008	49.189
2009	48.988
2010	48.722
2011	48.549
2012	48.316
2013	48.044
2014	47.734
2015	47.412
2016	47.112
2017	46.992
2018	46.868
2019	46.741
2020	46.615
2021	46.492
2022	46.369