Year	Percent
1991	68.022
1992	67.078
1993	66.926
1994	65.266
1995	64.776
1996	64.427
1997	64.149
1998	64.152
1999	63.892
2000	64.764
2001	64.066
2002	64.64
2003	62.483
2004	61.955
2005	62.398
2006	61.934
2007	61.181
2008	60.624
2009	63.191
2010	62.888
2011	61.987
2012	62.222
2013	61.984
2014	62.186
2015	61.192
2016	59.858
2017	59.977
2018	59.969
2019	59.963
2020	59.904
2021	59.714
2022	59.526