Year	Percent
1991	58.258
1992	57.827
1993	56.496
1994	56.154
1995	56.511
1996	56.245
1997	56.171
1998	55.839
1999	56.527
2000	58.103
2001	56.87
2002	56.29
2003	55.46
2004	56.02
2005	56.628
2006	56.292
2007	57.054
2008	56.902
2009	55.7
2010	55.864
2011	55.432
2012	55.153
2013	54.545
2014	54.027
2015	53.768
2016	54.212
2017	54.558
2018	54.716
2019	54.495
2020	54.18
2021	53.773
2022	53.356