Year	Percent
1991	93.98
1992	93.561
1993	93.731
1994	95.314
1995	94.597
1996	94.308
1997	94.081
1998	94.087
1999	93.977
2000	93.878
2001	93.694
2002	93.228
2003	92.952
2004	92.53
2005	91.926
2006	91.281
2007	90.543
2008	89.67
2009	89.001
2010	88.09
2011	87.151
2012	85.947
2013	83.04
2014	78.416
2015	77.424
2016	77.071
2017	76.66
2018	75.924
2019	75.129
2020	74.284
2021	73.393
2022	72.474