Year	Percent
1991	55.82
1992	56.654
1993	56.499
1994	56.351
1995	56.211
1996	56.069
1997	55.929
1998	55.79
1999	55.653
2000	55.517
2001	55.382
2002	55.271
2003	55.557
2004	56.118
2005	56.667
2006	56.27
2007	55.865
2008	55.46
2009	55.075
2010	55.254
2011	55.444
2012	55.764
2013	56.771
2014	56.145
2015	55.416
2016	54.72
2017	54.755
2018	54.786
2019	54.828
2020	54.885
2021	54.954
2022	55.035