Year Percent 2000-01-01 36.675 2001-01-01 35.575 2002-01-01 34.550 2003-01-01 35.200 2004-01-01 34.150 2005-01-01 35.875 2006-01-01 38.400 2007-01-01 41.425 2008-01-01 44.050 2009-01-01 44.275 2010-01-01 45.225 2011-01-01 47.825 2012-01-01 49.225 2013-01-01 51.300 2014-01-01 53.125 2015-01-01 54.150 2016-01-01 55.675 2017-01-01 58.300