Year Percent 2005-01-01 2.37 2006-01-01 2.48 2007-01-01 2.27 2008-01-01 2.23 2009-01-01 2.62 2010-01-01 2.73 2011-01-01 3.15 2012-01-01 3.24 2013-01-01 3.77 2014-01-01 3.72 2015-01-01 3.94 2016-01-01 4.86