Year Number 2004-01-01 9.7434 2005-01-01 9.7916 2006-01-01 10.1936 2007-01-01 11.3351 2008-01-01 11.0136 2009-01-01 10.4696 2010-01-01 9.8972 2011-01-01 9.3087 2012-01-01 6.8993 2013-01-01 5.9656 2014-01-01 5.5645 2015-01-01 4.8729 2016-01-01 4.5674