Year	Percent
1991	59.368
1992	60.98
1993	62.386
1994	62.707
1995	62.434
1996	60.419
1997	59.422
1998	58.987
1999	59.031
2000	59.033
2001	58.317
2002	58.272
2003	58.547
2004	59.021
2005	59.575
2006	57.85
2007	57.504
2008	56.79
2009	58.137
2010	60.948
2011	60.669
2012	60.016
2013	59.267
2014	58.783
2015	58.794
2016	57.113
2017	56.498
2018	56.639
2019	57.031
2020	57.373
2021	55.448
2022	54.336