Year	Percent
1991	93.326
1992	93.151
1993	92.88
1994	92.747
1995	91.794
1996	91.335
1997	91.107
1998	90.871
1999	90.535
2000	90.263
2001	89.983
2002	89.676
2003	89.297
2004	85.759
2005	80.254
2006	72.05
2007	75.686
2008	74.844
2009	72.293
2010	65.936
2011	68.322
2012	76.364
2013	66.312
2014	66.882
2015	66.416
2016	65.385
2017	65.295
2018	64.143
2019	63.316
2020	64.504
2021	65.204
2022	64.395