Year Percent 1999-01-01 33.025 2000-01-01 34.625 2001-01-01 37.500 2002-01-01 36.700 2003-01-01 34.500 2004-01-01 42.525 2005-01-01 45.400 2006-01-01 45.775 2007-01-01 46.625 2008-01-01 46.375 2009-01-01 48.200 2010-01-01 47.550 2011-01-01 42.675 2012-01-01 43.625 2013-01-01 45.125 2014-01-01 45.700 2015-01-01 46.350 2016-01-01 47.100 2017-01-01 51.775