Year	Percent
1991	91.326
1992	92.118
1993	91.663
1994	91.152
1995	91.723
1996	91.356
1997	91.396
1998	91.92
1999	92.487
2000	92.323
2001	92.571
2002	92.92
2003	92.699
2004	92.484
2005	92.419
2006	92.557
2007	92.378
2008	92.488
2009	92.261
2010	92.159
2011	92.011
2012	91.483
2013	91.413
2014	91.211
2015	91.305
2016	91.137
2017	91.076
2018	91.045
2019	91.011
2020	90.978
2021	90.947
2022	90.914