Year	Percent
1990	62.22
1991	62.12
1992	62.09
1993	62.07
1994	62.02
1995	61.91
1996	61.84
1997	61.72
1998	61.69
1999	60.71
2000	59.63
2001	59.97
2002	60.33
2003	60.67
2004	61
2005	61.28
2006	61.55
2007	62.64
2008	63.68
2009	64.66
2010	61.67
2011	66.02
2012	69.7
2013	72.85
2014	72.93
2015	73.07
2016	73.09
2017	73.11
2018	73.07
2019	73.05