Year Percent 2000-01-01 27.075 2001-01-01 26.200 2002-01-01 26.275 2003-01-01 27.050 2004-01-01 28.425 2005-01-01 28.975 2006-01-01 29.225 2007-01-01 27.250 2008-01-01 26.825 2009-01-01 27.200 2010-01-01 30.975 2011-01-01 31.900 2012-01-01 30.775 2013-01-01 30.800 2014-01-01 32.625 2015-01-01 31.525 2016-01-01 31.800 2017-01-01 31.650