Year	Percent
1991	92.818
1992	92.691
1993	92.701
1994	92.401
1995	92.438
1996	92.465
1997	92.435
1998	92.375
1999	92.295
2000	92.38
2001	92.381
2002	92.395
2003	92.362
2004	92.388
2005	92.366
2006	92.333
2007	92.23
2008	92.143
2009	92.151
2010	92.075
2011	91.989
2012	91.869
2013	91.774
2014	91.709
2015	91.783
2016	91.91
2017	91.865
2018	91.821
2019	91.776
2020	91.743
2021	91.705
2022	91.7