Year	Percent
1990	61.47
1991	61.27
1992	60.67
1993	61.42
1994	61.93
1995	62.88
1996	60.98
1997	63.15
1998	64.85
1999	64.32
2000	63.29
2001	65.68
2002	65.22
2003	65.54
2004	64.39
2005	66.68
2006	66.4
2007	67.47
2008	67.17
2009	66.92
2010	65.71
2011	65.31
2012	69.05
2013	68.75
2014	68.7
2015	67.67
2016	65.39
2017	66.37
2018	68.61
2019	71.15