Year	Percent
1991	93.944
1992	93.728
1993	93.83
1994	93.472
1995	93.503
1996	93.301
1997	92.953
1998	92.405
1999	91.981
2000	91.49
2001	91.039
2002	91.062
2003	91.042
2004	90.838
2005	90.549
2006	90.505
2007	90.306
2008	90.327
2009	90.297
2010	90.09
2011	89.85
2012	89.596
2013	89.238
2014	88.933
2015	88.845
2016	88.716
2017	88.684
2018	88.635
2019	88.579
2020	88.518
2021	88.458
2022	88.376