Year	Percent
1995	62.82867
1996	62.68431
1997	62.14785
1998	62.74611
1999	63.4543
2000	63.27009
2001	64.40575
2002	64.89511
2003	65.67563
2004	65.55739
2005	66.12982
2006	66.14342
2007	66.14675
2008	67.0593
2009	68.46736
2010	67.94614
2011	68.33239
2012	68.59856
2013	68.86439
2014	69.14405
2015	69.00287
2016	68.85387
2017	68.83149