Year	Percent
1991	53.51
1992	55.58
1993	53.66
1994	53.3
1995	54.22
1996	54.25
1997	57.16
1998	60.55
1999	62.77
2000	68.38
2001	70.22
2002	70.3
2003	68.58
2004	66.17
2005	59.33
2006	60.49
2007	63.11
2008	64.32
2009	62.93
2010	60.72
2011	61.23
2012	61.02
2013	59.98
2014	58.71
2015	60.75
2016	60.83
2017	62.28
2018	63.89
2019	65.19