Year	Percent
1991	62.434
1992	62.242
1993	62.235
1994	62.238
1995	62.245
1996	62.243
1997	62.193
1998	62.201
1999	62.226
2000	62.295
2001	62.201
2002	62.37
2003	62.458
2004	63.737
2005	62.868
2006	61.988
2007	61.111
2008	60.255
2009	59.399
2010	58.535
2011	57.661
2012	56.773
2013	55.911
2014	55.126
2015	55.016
2016	55.136
2017	55.044
2018	54.951
2019	54.856
2020	54.743
2021	54.617
2022	54.493