Year	Percent
1991	56.246
1992	57.197
1993	57.951
1994	58.337
1995	58.522
1996	58.15
1997	55.991
1998	55.178
1999	54.557
2000	53.594
2001	53.698
2002	53.753
2003	54.984
2004	55.095
2005	55.149
2006	55.204
2007	55.23
2008	55.993
2009	56.733
2010	57.952
2011	57.709
2012	57.382
2013	56.93
2014	56.671
2015	56.4
2016	56.126
2017	56.018
2018	55.918
2019	55.834
2020	55.773
2021	55.723
2022	55.692