Year Number 2004-01-01 28.8391 2005-01-01 30.7221 2006-01-01 30.7660 2007-01-01 32.6671 2008-01-01 34.3629 2009-01-01 35.6782 2010-01-01 35.1755 2011-01-01 35.9276 2012-01-01 35.6191 2013-01-01 34.6534 2014-01-01 33.9137 2015-01-01 33.6006 2016-01-01 32.8607