Year Number 2004-01-01 36.8647477361476 2005-01-01 42.2515457803998 2006-01-01 41.9412932056175 2007-01-01 54.1872827791003 2008-01-01 55.9593797677589 2009-01-01 55.2314546187662 2010-01-01 58.8074040560453 2011-01-01 57.2573970293309 2012-01-01 55.4649986977493 2013-01-01 55.4649237130750 2014-01-01 50.6730327218468