Year	Percent
1991	56.587
1992	58.843
1993	60.865
1994	62.348
1995	64.17
1996	65.754
1997	67.986
1998	68.832
1999	67.185
2000	67.012
2001	66.444
2002	66.169
2003	66.399
2004	66.032
2005	65.529
2006	66.06
2007	66.535
2008	65.65
2009	65.674
2010	65.494
2011	64.975
2012	64.888
2013	64.976
2014	65.309
2015	65.809
2016	66.079
2017	66.05
2018	66.018
2019	65.986
2020	65.955
2021	65.922
2022	65.888