Year	Percent
1990	44.79
1991	45.3
1992	45.67
1993	45.71
1994	45.99
1995	45.66
1996	45.6
1997	45.86
1998	45.96
1999	45.98
2000	45.69
2001	45.43
2002	45.31
2003	45.12
2004	44.86
2005	44.57
2006	44.43
2007	44.03
2008	43.89
2009	44.09
2010	44.01
2011	43.92
2012	44.3
2013	44.48
2014	44.62
2015	44.5
2016	44.05
2017	43.96
2018	44.01
2019	43.72
2020	43.02