Year	Percent
1996	72.25866
1997	72.21861
1998	67.94458
1999	65.31704
2000	67.20639
2001	65.85076
2002	65.99108
2003	64.87926
2006	67.92247
2007	68.95863
2008	69.6888
2010	73.4721
2011	73.32261
2012	74.69719
2013	74.46412
2014	73.99085
2015	74.13104
2016	73.28884
2017	72.14808