Year	Percent
1991	78.812
1992	79.261
1993	78.594
1994	78.213
1995	78.999
1996	79.87
1997	81.206
1998	81.004
1999	81.056
2000	81.897
2001	81.949
2002	82.639
2003	83.45
2004	83.43
2005	84.484
2006	84.354
2007	84.973
2008	84.845
2009	85.756
2010	85.893
2011	85.997
2012	86.287
2013	86.473
2014	86.408
2015	85.932
2016	86.669
2017	86.454
2018	86.683
2019	86.948
2020	87.13
2021	87.299
2022	87.422