Year	Percent
1991	73.853
1992	72.498
1993	71.678
1994	70.706
1995	71.003
1996	72.385
1997	72.924
1998	72.989
1999	73.218
2000	73.561
2001	73.643
2002	73.615
2003	71.664
2004	68.499
2005	67.887
2006	68.199
2007	66.919
2008	67.127
2009	67.424
2010	67.645
2011	67.634
2012	67.79
2013	67.337
2014	67.149
2015	67.418
2016	67.673
2017	67.364
2018	67.391
2019	67.344
2020	67.495
2021	67.655
2022	67.824