Year	Percent
1991	69.273
1992	69.494
1993	69.533
1994	69.831
1995	69.593
1996	68.92
1997	69.123
1998	67.917
1999	66.864
2000	65.753
2001	64.668
2002	58.852
2003	58.287
2004	56.939
2005	56.414
2006	57.099
2007	57.703
2008	58.167
2009	57.497
2010	59.437
2011	57.905
2012	58.905
2013	58.635
2014	59.238
2015	59.384
2016	59.275
2017	59.595
2018	59.49
2019	58.922
2020	58.769
2021	58.518
2022	58.265