Year	Percent
1991	92.103
1992	92.094
1993	91.971
1994	91.57
1995	91.308
1996	90.957
1997	90.98
1998	90.995
1999	91.054
2000	90.796
2001	91.292
2002	91.276
2003	91.052
2004	90.385
2005	89.843
2006	89.104
2007	88.363
2008	88.213
2009	88.065
2010	87.468
2011	83.341
2012	83.169
2013	82.9
2014	82.709
2015	82.389
2016	81.974
2017	81.936
2018	81.856
2019	81.782
2020	81.709
2021	81.64
2022	81.573