Year	Percent
1991	79.62
1992	77.978
1993	77.527
1994	75.648
1995	67.636
1996	67.066
1997	66.396
1998	66.546
1999	65.469
2000	64.587
2001	63.364
2002	61.869
2003	60.999
2004	60.764
2005	60.454
2006	59.374
2007	65.059
2008	64.762
2009	63.982
2010	61.898
2011	60.147
2012	56.478
2013	60.896
2014	60.489
2015	63.268
2016	63.083
2017	63.12
2018	62.92
2019	62.808
2020	62.704
2021	62.607
2022	62.535