Year Number 2004-01-01 35.2574 2005-01-01 37.4870 2006-01-01 38.3100 2007-01-01 41.9355 2008-01-01 45.5801 2009-01-01 47.8564 2010-01-01 51.3976 2011-01-01 49.7337 2012-01-01 38.9737 2013-01-01 47.7062 2014-01-01 33.2962 2015-01-01 42.0211 2016-01-01 45.5621 2017-01-01 44.2965