Year Percent 1999-01-01 31.050 2000-01-01 32.375 2001-01-01 35.850 2002-01-01 35.425 2003-01-01 33.200 2004-01-01 40.900 2005-01-01 43.150 2006-01-01 44.550 2007-01-01 45.225 2008-01-01 44.700 2009-01-01 46.375 2010-01-01 45.600 2011-01-01 39.475 2012-01-01 40.750 2013-01-01 41.775 2014-01-01 41.750 2015-01-01 42.600 2016-01-01 43.575 2017-01-01 48.000