Year Number 2004-01-01 0.5800 2005-01-01 0.9524 2006-01-01 1.5111 2007-01-01 1.9400 2008-01-01 2.2691 2009-01-01 2.2713 2010-01-01 1.9676 2011-01-01 1.9446 2012-01-01 1.9487 2013-01-01 1.9343 2014-01-01 1.8167 2015-01-01 1.8727 2016-01-01 2.1959 2017-01-01 2.3422