Year	Percent
1991	47.84
1992	47.92
1993	48.78
1994	49.21
1995	50.1
1996	49.29
1997	48.84
1998	48.52
1999	48.26
2000	49.29
2001	48.95
2002	48.1
2003	46.67
2004	45.76
2005	44.88
2006	43.49
2007	43.22
2008	42.35
2009	39.93
2010	38.62
2011	39.5
2012	38.48
2013	39.35
2014	39.71
2015	42.48
2016	41
2017	40.61
2018	37.05
2019	39.39
2020	37.77