Year	Percent
2003-01-01	28.5
2004-01-01	21.6
2005-01-01	18.6
2006-01-01	18.1
2007-01-01	17.1
2008-01-01	17.2
2009-01-01	16.2
2010-01-01	15.4
2011-01-01	15.6
2012-01-01	16.2
2013-01-01	17.9
2014-01-01	16.8
2015-01-01	15.7