Year	Percent
2002	68.94518
2003	68.65785
2004	68.71496
2005	69.62331
2006	70.0855
2007	70.31799
2008	71.00222
2009	70.03403
2010	71.14834
2011	70.48962
2012	71.23464
2013	71.31365
2014	72.02665
2015	71.88611
2016	71.89931
2017	72.23332