Year	Percent
1991	57.111
1992	54.69
1993	54.241
1994	52.548
1995	55.599
1996	53.684
1997	53.629
1998	53.076
1999	52.568
2000	52.704
2001	54.519
2002	51.167
2003	53.724
2004	49.005
2005	46.622
2006	47.71
2007	49.184
2008	48.517
2009	46.121
2010	46.145
2011	48.296
2012	46.761
2013	47.317
2014	45.677
2015	45.903
2016	47.932
2017	47.909
2018	47.693
2019	47.377
2020	46.949
2021	46.326
2022	45.526