Year	Percent
1990	65.06
1991	65.3
1992	65.27
1993	65.18
1994	65.14
1995	65.05
1996	65.03
1997	64.94
1998	64.83
1999	64.67
2000	64.51
2001	64.37
2002	64.72
2003	64.41
2004	64.19
2005	63.96
2006	64.09
2007	64.23
2008	64.37
2009	64.52
2010	64.67
2011	64.85
2012	65.03
2013	64.65
2014	64.28
2015	63.9
2016	63.66
2017	63.45
2018	63.22
2019	62.98