Year	Percent
1991	66.754
1992	66.693
1993	66.752
1994	66.525
1995	65.796
1996	65.005
1997	64.263
1998	63.529
1999	62.773
2000	62.618
2001	62.366
2002	62.186
2003	62.014
2004	61.857
2005	62.375
2006	61.809
2007	61.658
2008	61.525
2009	61.43
2010	60.229
2011	59.622
2012	59.68
2013	59.551
2014	59.258
2015	60.064
2016	60.774
2017	60.708
2018	60.744
2019	60.966
2020	61.047
2021	60.977
2022	60.896