Year Number 2004-01-01 24.1461 2005-01-01 25.8900 2006-01-01 25.4217 2007-01-01 31.1701 2008-01-01 26.4195 2009-01-01 24.9476 2010-01-01 35.8213 2011-01-01 35.3943 2012-01-01 38.1770 2013-01-01 27.0409 2014-01-01 25.2713 2015-01-01 32.0075 2016-01-01 27.9386