Year	Percent
1998-01-01	51.6645
1999-01-01	51.5219
2000-01-01	54.8000
2001-01-01	57.3000
2002-01-01	58.4132
2003-01-01	56.6788
2004-01-01	55.1842
2005-01-01	52.8932
2006-01-01	55.7780
2007-01-01	50.6728
2008-01-01	50.7484
2009-01-01	51.7552
2010-01-01	54.5532
2011-01-01	52.8159
2012-01-01	56.3540
2013-01-01	59.3588
2014-01-01	62.6301
2015-01-01	66.6838
2016-01-01	66.2457