Year Number 2004-01-01 1.7480 2005-01-01 7.6247 2006-01-01 11.8389 2007-01-01 10.9813 2008-01-01 11.5539 2009-01-01 8.3558 2010-01-01 8.1217 2011-01-01 7.8880 2012-01-01 6.2326 2013-01-01 4.9149 2014-01-01 4.8589 2015-01-01 4.6602 2016-01-01 4.5873 2017-01-01 4.4301