Year	Percent
1991	59.557
1992	59.613
1993	59.276
1994	58.374
1995	58.407
1996	58.366
1997	57.704
1998	57.638
1999	58.01
2000	58.389
2001	57.999
2002	57.056
2003	55.95
2004	53.556
2005	53.476
2006	52.714
2007	53.446
2008	55.015
2009	51.535
2010	48.432
2011	46.289
2012	46.129
2013	48.191
2014	49.769
2015	50.131
2016	53.042
2017	53.403
2018	53.664
2019	53.849
2020	53.969
2021	53.991
2022	53.971