Year	Percent
1991	64.53
1992	63.965
1993	63.62
1994	63.143
1995	63.055
1996	62.727
1997	62.471
1998	62.139
1999	59.576
2000	59.246
2001	58.895
2002	59.125
2003	58.791
2004	58.645
2005	57.941
2006	57.179
2007	56.368
2008	55.73
2009	54.73
2010	54.132
2011	59.723
2012	59.112
2013	58.357
2014	57.666
2015	57.032
2016	56.175
2017	55.994
2018	55.901
2019	55.811
2020	55.725
2021	55.639
2022	55.555