Year Number 2004-01-01 6.5164 2005-01-01 6.8249 2006-01-01 6.8605 2007-01-01 7.0004 2008-01-01 7.0965 2009-01-01 7.4079 2010-01-01 9.7439 2011-01-01 9.8477 2012-01-01 9.9748 2013-01-01 11.5613 2014-01-01 12.9858 2015-01-01 15.4658 2016-01-01 18.8670