Year Number 2004-01-01 12.6222 2005-01-01 12.6671 2006-01-01 12.7701 2007-01-01 13.0124 2008-01-01 13.1772 2009-01-01 12.9350 2010-01-01 12.8185 2011-01-01 12.4569 2012-01-01 12.0497 2013-01-01 11.5312 2014-01-01 11.3234 2015-01-01 11.2718 2016-01-01 11.0105 2017-01-01 10.7325