Year	Percent
1991	86.634
1992	86.5
1993	86.306
1994	85.878
1995	85.401
1996	84.196
1997	83.389
1998	83.333
1999	82.521
2000	80.835
2001	80.924
2002	79.762
2003	77.824
2004	76.305
2005	77.194
2006	76.206
2007	75.785
2008	75.393
2009	76.08
2010	74.687
2011	74.034
2012	73.984
2013	73.734
2014	73.269
2015	72.848
2016	72.197
2017	72.046
2018	71.969
2019	71.889
2020	71.809
2021	71.727
2022	71.656