Year	Percent
1991	64.958
1992	65.459
1993	65.005
1994	64.554
1995	65.57
1996	66.6
1997	67.022
1998	64.105
1999	63.474
2000	64.291
2001	63.978
2002	64.393
2003	64.529
2004	64.472
2005	64.895
2006	64.055
2007	64.566
2008	64.605
2009	63.853
2010	64.054
2011	65.522
2012	64.827
2013	62.714
2014	62.106
2015	60.591
2016	60.061
2017	59.783
2018	59.479
2019	59.178
2020	59.026
2021	58.841
2022	58.619