Year	Percent
1991	64.713
1992	64.992
1993	62.884
1994	62.525
1995	61.645
1996	61.928
1997	62.164
1998	61.173
1999	62.508
2000	62.582
2001	62.087
2002	62.224
2003	61.953
2004	63.099
2005	64.003
2006	66.901
2007	65.347
2008	63.678
2009	62.678
2010	62.9
2011	61.084
2012	60.436
2013	59.622
2014	59.061
2015	58.25
2016	60.395
2017	59.834
2018	59.342
2019	58.851
2020	58.29
2021	57.677
2022	57.003