Year Number 2007-01-01 531.3663 2008-01-01 540.6025 2009-01-01 546.2931 2010-01-01 548.0988 2011-01-01 673.4434 2012-01-01 674.6074 2013-01-01 673.0110 2014-01-01 668.9431 2015-01-01 665.9174 2016-01-01 664.4833 2017-01-01 665.1915