Year Number 2004-01-01 7.7449 2005-01-01 10.5820 2006-01-01 12.7088 2007-01-01 15.4390 2008-01-01 19.6184 2009-01-01 23.3126 2010-01-01 25.7588 2011-01-01 28.5418 2012-01-01 30.9165 2013-01-01 33.5746 2014-01-01 36.1262 2015-01-01 32.4858 2016-01-01 34.9398 2017-01-01 36.7102