Year	Percent
1991	86.975
1992	86.775
1993	86.797
1994	86.985
1995	87.236
1996	86.664
1997	86.214
1998	85.998
1999	86.024
2000	86.214
2001	85.426
2002	84.923
2003	84.908
2004	85.232
2005	85.707
2006	85.412
2007	85.507
2008	85.894
2009	86.442
2010	86.999
2011	86.232
2012	86.439
2013	86.574
2014	86.656
2015	86.599
2016	86.554
2017	86.549
2018	86.643
2019	86.828
2020	87.092
2021	86.331
2022	85.814