Year	Percent
1991	58.975
1992	56.99
1993	57.355
1994	60.182
1995	62.268
1996	61.878
1997	60.477
1998	61.185
1999	61.991
2000	62.555
2001	61.604
2002	61.653
2003	62.27
2004	62.684
2005	64.166
2006	64.424
2007	64.939
2008	65.424
2009	61.566
2010	61.341
2011	60.594
2012	59.702
2013	58.593
2014	57.539
2015	58.275
2016	57.983
2017	57.797
2018	57.574
2019	57.067
2020	56.811
2021	56.49
2022	56.135