Year	Percent
1991	79.765
1992	81.287
1993	81.637
1994	80.996
1995	81.065
1996	81.609
1997	82.388
1998	83.355
1999	83.728
2000	83.583
2001	84.278
2002	84.98
2003	85.508
2004	85.816
2005	86.157
2006	86.098
2007	86.479
2008	85.92
2009	86.786
2010	86.61
2011	86.739
2012	86.744
2013	86.584
2014	86.717
2015	87.031
2016	87.257
2017	86.864
2018	87.107
2019	87.302
2020	87.48
2021	87.657
2022	87.837