Year	Percent
1996	74.48082
1997	74.01194
1998	58.0272
1999	57.45275
2000	59.76179
2001	59.266
2002	59.94822
2003	58.19408
2006	61.61329
2007	62.85931
2008	63.49056
2010	74.47812
2011	72.9715
2012	74.05666
2013	74.05249
2014	73.61128
2015	73.99992
2016	73.0954
2017	72.64275