Year	Percent
1991	58.358
1992	59.102
1993	55.392
1994	56.001
1995	54.878
1996	52.296
1997	51.175
1998	51.037
1999	50.591
2000	48.67
2001	47.24
2002	47.696
2003	46.23
2004	45.076
2005	48.437
2006	48.806
2007	50.666
2008	51.329
2009	50.455
2010	48.847
2011	49.716
2012	50.213
2013	49.79
2014	49.962
2015	48.861
2016	49.018
2017	49.912
2018	50.057
2019	50.037
2020	49.949
2021	49.908
2022	49.958