Year	Percent
2005-01-01	39.9
2006-01-01	39.4
2007-01-01	39.2
2008-01-01	38.8
2009-01-01	38.6
2010-01-01	38.5
2011-01-01	38.3
2012-01-01	37.9
2013-01-01	37.5
2014-01-01	37.3
2015-01-01	37.1
2016-01-01	36.5