Year	Percent
1991	47.29
1992	46.97
1993	46.65
1994	46.4
1995	46.22
1996	45.83
1997	45.22
1998	44.61
1999	43.94
2000	43.26
2001	43.2
2002	43.41
2003	43.86
2004	43.03
2005	42.2
2006	42.42
2007	41.65
2008	40.87
2009	39.9
2010	40.44
2011	39.39
2012	38.29
2013	37.15
2014	36.47
2015	35.78
2016	35.11
2017	36.79
2018	36.88
2019	36.88