Year Percent 2001-01-01 1.92 2002-01-01 2.22 2003-01-01 2.42 2004-01-01 2.62 2005-01-01 2.79 2006-01-01 3.22 2007-01-01 3.41 2008-01-01 3.01 2009-01-01 3.59 2010-01-01 2.88 2011-01-01 2.56 2012-01-01 2.59 2013-01-01 2.46 2014-01-01 2.80 2015-01-01 3.06 2016-01-01 4.56