Year	Percent
1991	66.428
1992	66.874
1993	67.052
1994	67.464
1995	67.144
1996	66.828
1997	66.338
1998	58.811
1999	58.661
2000	58.579
2001	58.37
2002	57.94
2003	57.913
2004	57.52
2005	57.147
2006	56.827
2007	56.405
2008	56.106
2009	55.161
2010	54.624
2011	57.147
2012	64.797
2013	63.472
2014	63.099
2015	64.604
2016	66.646
2017	67.838
2018	68.156
2019	68.289
2020	68.002
2021	66.996
2022	66.646