Year	Percent
1991	85.652
1992	85.47
1993	85.395
1994	85.282
1995	85.188
1996	85.097
1997	85.032
1998	84.97
1999	84.782
2000	84.54
2001	84.35
2002	84.149
2003	83.892
2004	83.624
2005	83.328
2006	83.03
2007	82.732
2008	82.458
2009	82.108
2010	81.742
2011	81.491
2012	81.16
2013	80.771
2014	80.376
2015	79.984
2016	79.597
2017	79.294
2018	78.996
2019	78.724
2020	78.487
2021	78.265
2022	78.081