Year	Percent
1991	87.033
1992	86.689
1993	86.606
1994	86.308
1995	86.267
1996	85.959
1997	85.538
1998	85.139
1999	84.864
2000	84.227
2001	83.913
2002	83.152
2003	82.916
2004	82.146
2005	81.332
2006	80.38
2007	78.765
2008	78.097
2009	78.346
2010	77.785
2011	77.206
2012	77.267
2013	77.155
2014	76.872
2015	76.795
2016	76.057
2017	75.763
2018	75.259
2019	74.793
2020	74.296
2021	73.849
2022	73.373