Year	Percent
1991	92.026
1992	91.868
1993	91.853
1994	91.647
1995	91.74
1996	92.07
1997	92.049
1998	92.103
1999	92.164
2000	91.987
2001	91.927
2002	92.085
2003	91.886
2004	92.048
2005	92.039
2006	92.071
2007	91.824
2008	91.589
2009	91.544
2010	91.41
2011	89.728
2012	89.459
2013	89.173
2014	89.033
2015	89.144
2016	89.117
2017	89.194
2018	89.164
2019	89.132
2020	89.099
2021	89.065
2022	89.035