Year	Percent
1991	80.148
1992	79.774
1993	79.84
1994	79.902
1995	79.951
1996	79.989
1997	79.3
1998	79.574
1999	79.485
2000	79.862
2001	80.489
2002	80.217
2003	80.547
2004	80.279
2005	79.645
2006	79.306
2007	78.576
2008	78.363
2009	79.46
2010	79.627
2011	79.88
2012	80.45
2013	80.401
2014	80.252
2015	78.946
2016	78.362
2017	78.249
2018	78.008
2019	77.789
2020	77.599
2021	77.419
2022	77.268