Year	Percent
1991	66.265
1992	67.004
1993	67.009
1994	66.912
1995	66.398
1996	67.645
1997	69.308
1998	68.961
1999	67.362
2000	67.338
2001	67.547
2002	67.304
2003	68.401
2004	68.124
2005	67.754
2006	67.576
2007	66.839
2008	66.955
2009	66.344
2010	65.932
2011	65.639
2012	64.991
2013	64.034
2014	64.376
2015	64.148
2016	63.809
2017	63.942
2018	63.891
2019	63.837
2020	63.778
2021	63.72
2022	63.66