Year	Percent
1991	62.623
1992	58.554
1993	55.317
1994	55.37
1995	55.539
1996	56.123
1997	57.874
1998	58.492
1999	57.522
2000	58.019
2001	57.706
2002	57.003
2003	55.588
2004	56.513
2005	55.708
2006	54.683
2007	54.009
2008	53.415
2009	48.064
2010	47.659
2011	46.187
2012	46.21
2013	46.088
2014	47.886
2015	49.985
2016	50.136
2017	50.723
2018	51.14
2019	50.95
2020	50.343
2021	49.651
2022	48.907