Year	Percent
1991	87.593
1992	87.358
1993	87.175
1994	83.921
1995	84.328
1996	84.644
1997	85.552
1998	85.28
1999	85.034
2000	84.795
2001	84.364
2002	85.907
2003	84.888
2004	91.114
2005	90.936
2006	90.741
2007	90.342
2008	90.023
2009	90.849
2010	90.691
2011	89.102
2012	88.993
2013	89.76
2014	89.651
2015	89.412
2016	89.436
2017	89.419
2018	89.384
2019	89.349
2020	89.313
2021	89.279
2022	89.244