Year Number 2004-01-01 22.3039 2005-01-01 32.0279 2006-01-01 36.6563 2007-01-01 40.9950 2008-01-01 45.7734 2009-01-01 44.1850 2010-01-01 41.7891 2011-01-01 40.2906 2012-01-01 38.0650 2013-01-01 33.9072 2014-01-01 30.6047 2015-01-01 29.7661 2016-01-01 29.7226 2017-01-01 28.1261