Year	Percent
1991	82.981
1992	83.01
1993	83.048
1994	83.117
1995	83.257
1996	83.099
1997	82.775
1998	82.734
1999	82.487
2000	82.435
2001	82.151
2002	82.598
2003	82.217
2004	81.935
2005	81.61
2006	81.111
2007	80.454
2008	80.126
2009	79.813
2010	79.482
2011	79.078
2012	78.881
2013	78.597
2014	78.324
2015	78.197
2016	77.971
2017	77.944
2018	77.893
2019	77.84
2020	77.783
2021	77.727
2022	77.669