Year	Percent
1991	43
1992	44.29
1993	44.85
1994	45.08
1995	44.81
1996	45.18
1997	45.37
1998	44.41
1999	42.58
2000	42.32
2001	41.69
2002	40.77
2003	40.17
2004	39.82
2005	40.47
2006	41.06
2007	41.11
2008	41.06
2009	39.57
2010	38.92
2011	39.06
2012	38.9
2013	40
2014	40.37
2015	40.49
2016	42.19
2017	42.49
2018	45.68
2019	46.95