Year	Percent
1991	89.209
1992	88.883
1993	88.919
1994	87.704
1995	88.618
1996	88.482
1997	88.458
1998	88.052
1999	87.686
2000	87.841
2001	87.597
2002	87.721
2003	87.381
2004	86.324
2005	85.468
2006	86.484
2007	86.2
2008	86.014
2009	85.651
2010	85.37
2011	85.222
2012	84.134
2013	84.129
2014	83.905
2015	84.16
2016	84.385
2017	84.087
2018	83.917
2019	83.716
2020	83.467
2021	83.214
2022	82.939