Year	Percent
1991	83.873
1992	83.681
1993	83.457
1994	82.841
1995	83.649
1996	83.049
1997	83.09
1998	82.899
1999	82.693
2000	82.497
2001	86.997
2002	86.991
2003	86.554
2004	85.854
2005	85.144
2006	84.306
2007	83.419
2008	83.345
2009	82.884
2010	82.026
2011	80.218
2012	79.975
2013	79.541
2014	79.145
2015	78.651
2016	78.141
2017	78.097
2018	78.008
2019	77.923
2020	77.841
2021	77.763
2022	77.687