Year	Percent
1991	61.785
1992	61.612
1993	61.974
1994	61.65
1995	61.338
1996	61.094
1997	60.857
1998	60.602
1999	60.421
2000	60.146
2001	60.158
2002	60.185
2003	60.011
2004	59.229
2005	59.08
2006	58.928
2007	58.771
2008	58.604
2009	58.429
2010	58.243
2011	58.026
2012	57.809
2013	57.582
2014	56.862
2015	56.987
2016	55.32
2017	55.23
2018	55.126
2019	55.007
2020	54.891
2021	54.761
2022	54.634