Year Number 2004-01-01 5.6715 2005-01-01 6.2193 2006-01-01 18.5252 2007-01-01 21.1838 2008-01-01 22.0597 2009-01-01 19.1933 2010-01-01 7.5689 2011-01-01 7.0910 2012-01-01 6.8172 2013-01-01 7.0595 2014-01-01 7.5325 2015-01-01 6.7794 2016-01-01 5.3159