Year	Percent
1991	79.474
1992	79.547
1993	80.546
1994	81.546
1995	81.202
1996	84.03
1997	84.044
1998	84.043
1999	84.168
2000	83.945
2001	83.878
2002	83.627
2003	83.504
2004	83.346
2005	83.218
2006	82.925
2007	82.716
2008	82.697
2009	82.623
2010	82.574
2011	82.5
2012	82.452
2013	82.423
2014	82.406
2015	82.339
2016	82.146
2017	82.129
2018	82.219
2019	82.267
2020	82.267
2021	82.193
2022	82.088