Year	Percent
2001	74.03566
2002	75.02011
2003	76.43783
2004	80.27288
2005	82.58593
2006	78.56158
2007	74.45592
2008	68.39652
2009	67.01179
2010	67.1237
2011	68.72498
2012	70.02112
2013	69.80111
2014	69.43968
2015	71.00556
2016	70.77363
2017	71.37658