Year	Percent
1991	94.902
1992	94.511
1993	94.725
1994	94.519
1995	94.441
1996	94.183
1997	94.271
1998	94.336
1999	94.061
2000	93.918
2001	93.986
2002	93.779
2003	93.609
2004	93.051
2005	92.428
2006	92.315
2007	92.36
2008	92.227
2009	92.29
2010	92.152
2011	91.886
2012	91.913
2013	91.713
2014	91.612
2015	91.681
2016	91.838
2017	91.846
2018	91.831
2019	91.81
2020	91.791
2021	91.779
2022	91.766