Year	Percent
1991	44.88
1992	42.69
1993	45.4
1994	44.4
1995	46.73
1996	44.37
1997	44.52
1998	47.2
1999	46.21
2000	45.65
2001	46.18
2002	43.94
2003	41.36
2004	42.43
2005	42.73
2006	44.57
2007	43.85
2008	44.94
2009	39.88
2010	39.39
2011	39.1
2012	37.5
2013	36.22
2014	39.3
2015	41.71
2016	41.5
2017	43.27
2018	42.23
2019	41.81