Year	Percent
1990	43.29
1991	43.31
1992	43.26
1993	43.36
1994	43.53
1995	43.58
1996	43.69
1997	43.75
1998	43.81
1999	43.87
2000	43.93
2001	44
2002	44.05
2003	44.09
2004	44.13
2005	44.15
2006	44.17
2007	44.17
2008	44.15
2009	44.11
2010	44.04
2011	44.03
2012	44.01
2013	44.83
2014	45.69
2015	45.72
2016	45.72
2017	44.25
2018	44.56
2019	44.67