Year	Percent
1991	57.134
1992	57.961
1993	58.869
1994	59.553
1995	61.519
1996	61.65
1997	61.891
1998	63.076
1999	63.59
2000	63.206
2001	62.933
2002	62.727
2003	62.402
2004	61.536
2005	60.642
2006	62.902
2007	61.698
2008	61.113
2009	63.509
2010	65.453
2011	63.637
2012	66.169
2013	69.533
2014	68.727
2015	69.468
2016	68.465
2017	68.524
2018	68.755
2019	68.91
2020	69.055
2021	69.168
2022	69.301