Year Number 2004-01-01 341.9291 2005-01-01 341.7093 2006-01-01 336.1714 2007-01-01 377.3007 2008-01-01 423.4201 2009-01-01 488.6817 2010-01-01 488.4768 2011-01-01 455.1573 2012-01-01 557.0193 2013-01-01 600.9867 2014-01-01 618.8874 2015-01-01 608.8271 2016-01-01 583.1372