Year	Percent
1991	86.34
1992	86.088
1993	85.822
1994	85.592
1995	85.384
1996	85.252
1997	84.95
1998	84.638
1999	84.357
2000	84.104
2001	83.862
2002	83.61
2003	82.875
2004	83.009
2005	83.243
2006	83.629
2007	82.544
2008	81.771
2009	80.684
2010	81.001
2011	80.333
2012	79.671
2013	78.945
2014	78.374
2015	77.793
2016	77.262
2017	77.2
2018	77.142
2019	77.089
2020	77.038
2021	76.989
2022	76.948