Year	Percent
1990	42.06
1991	42.65
1992	42.71
1993	43.26
1994	43.74
1995	44.11
1996	44.16
1997	44.09
1998	44
1999	43.9
2000	43.81
2001	43.8
2002	43.34
2003	42.78
2004	42.81
2005	42.8
2006	42.63
2007	44.09
2008	43.86
2009	44.74
2010	43.99
2011	43.35
2012	42.44
2013	41.53
2014	41.55
2015	41.59
2016	41.65
2017	41.7
2018	41.75
2019	41.78