Year	Percent
1991	66.836
1992	66.74
1993	66.615
1994	66.546
1995	66.439
1996	66.355
1997	66.25
1998	66.146
1999	66.043
2000	65.942
2001	65.839
2002	66.135
2003	66.437
2004	66.738
2005	67.11
2006	67.585
2007	68.067
2008	67.832
2009	67.606
2010	67.122
2011	67.141
2012	67.175
2013	67.214
2014	67.253
2015	67.355
2016	67.443
2017	67.552
2018	67.641
2019	67.726
2020	67.805
2021	67.877
2022	67.942