Year	Percent
1990	62.23
1991	62.6
1992	63.01
1993	63.36
1994	63.65
1995	64.01
1996	64.36
1997	64.72
1998	65.05
1999	65.33
2000	65.56
2001	65.93
2002	66.31
2003	66.69
2004	67.03
2005	67.34
2006	67.5
2007	67.53
2008	67.45
2009	67.3
2010	67.09
2011	67.17
2012	67.25
2013	67.28
2014	67.24
2015	67.14
2016	67.17
2017	67.23
2018	67.31
2019	67.35
2020	63.87