Year Number 2008-01-01 577.2209 2009-01-01 553.4675 2010-01-01 522.1384 2011-01-01 611.6128 2012-01-01 581.9627 2013-01-01 544.3928 2014-01-01 517.6694 2015-01-01 512.1157 2016-01-01 505.2562