Year Number 2004-01-01 41.0098 2005-01-01 40.1881 2006-01-01 39.6880 2007-01-01 39.3180 2008-01-01 38.8406 2009-01-01 38.1544 2010-01-01 37.8231 2011-01-01 37.4656 2012-01-01 36.9542 2013-01-01 36.1700 2014-01-01 35.2995 2015-01-01 33.9496 2016-01-01 31.9060 2017-01-01 29.2663