Year	Percent
1991	62.787
1992	62.568
1993	62.284
1994	61.945
1995	61.527
1996	61.336
1997	61.099
1998	60.783
1999	60.443
2000	60.151
2001	59.684
2002	61.62
2003	61.365
2004	61.089
2005	60.801
2006	60.654
2007	61.137
2008	61.914
2009	63.436
2010	62.684
2011	61.905
2012	63.094
2013	64.375
2014	67.141
2015	66.993
2016	66.702
2017	66.662
2018	66.628
2019	66.621
2020	66.646
2021	66.697
2022	66.77