Year Number 2004-01-01 8.7717 2005-01-01 8.6838 2006-01-01 9.0594 2007-01-01 9.2932 2008-01-01 10.4058 2009-01-01 10.8511 2010-01-01 10.4773 2011-01-01 10.6957 2012-01-01 10.5004 2013-01-01 10.3109 2014-01-01 10.7602 2015-01-01 10.9539 2016-01-01 11.8303