Year	Percent
1991	96.64
1992	96.334
1993	96.307
1994	96.045
1995	95.847
1996	95.289
1997	94.879
1998	94.821
1999	94.134
2000	92.89
2001	92.613
2002	91.806
2003	92.511
2004	85.348
2005	86.374
2006	85.962
2007	85.341
2008	84.727
2009	86.047
2010	85.653
2011	85.191
2012	86.083
2013	85.468
2014	85.074
2015	84.463
2016	84.232
2017	84.14
2018	84.095
2019	84.048
2020	84.001
2021	83.952
2022	83.911