Year	Percent
1991	82.301
1992	82.109
1993	82.194
1994	82.964
1995	82.454
1996	82.613
1997	82.304
1998	82.542
1999	82.84
2000	83.113
2001	82.728
2002	82.261
2003	82.862
2004	83.501
2005	83.074
2006	82.96
2007	82.934
2008	83.049
2009	82.42
2010	82.672
2011	82.499
2012	82.444
2013	81.733
2014	81.06
2015	81.514
2016	82.899
2017	82.899
2018	82.749
2019	82.653
2020	82.565
2021	82.499
2022	82.404