Year	Percent
1990	62.62
1991	62.19
1992	61.74
1993	61.19
1994	61
1995	60.82
1996	60.87
1997	61.04
1998	60.94
1999	61.25
2000	61.44
2001	60.99
2002	61.25
2003	61.37
2004	61.42
2005	61.76
2006	62.09
2007	61.94
2008	62.21
2009	62.05
2010	61.87
2011	61.79
2012	62.04
2013	62.21
2014	62.31
2015	62.37
2016	62.51
2017	62.51
2018	62.75
2019	62.97
2020	62.78