Year	Percent
1991	59.083
1992	57.702
1993	56.844
1994	57.314
1995	56.4
1996	56.482
1997	55.385
1998	55.308
1999	54.118
2000	53.941
2001	54.032
2002	53.539
2003	52.954
2004	53.093
2005	53.674
2006	54.917
2007	55.385
2008	55.904
2009	55.45
2010	54.143
2011	52.993
2012	52.769
2013	54.135
2014	54.216
2015	53.346
2016	52.48
2017	53.851
2018	53.824
2019	53.797
2020	53.775
2021	53.75
2022	53.723