Year	Percent
1991	89.309
1992	88.825
1993	88.278
1994	87.665
1995	86.999
1996	86.274
1997	85.474
1998	84.6
1999	83.992
2000	83.345
2001	82.851
2002	82.369
2003	81.91
2004	81.48
2005	81.088
2006	80.687
2007	80.317
2008	79.976
2009	79.686
2010	79.441
2011	79.221
2012	79.043
2013	78.888
2014	78.668
2015	78.962
2016	79.217
2017	79.315
2018	79.379
2019	79.397
2020	79.361
2021	79.264
2022	79.119