Year	Percent
1991	85.385
1992	86.034
1993	85.722
1994	85.834
1995	85.895
1996	86.469
1997	84.791
1998	83.199
1999	81.836
2000	80.447
2001	80.875
2002	80.778
2003	80.804
2004	80.751
2005	81.062
2006	81.469
2007	81.073
2008	80.42
2009	80.076
2010	80.098
2011	80.189
2012	81.186
2013	81.589
2014	81.795
2015	82.528
2016	82.654
2017	82.395
2018	82.842
2019	83.094
2020	83.285
2021	83.49
2022	83.681