Year Number 2004-01-01 10.3186 2005-01-01 11.4427 2006-01-01 12.3260 2007-01-01 12.5162 2008-01-01 13.1889 2009-01-01 14.0265 2010-01-01 15.1246 2011-01-01 16.8331 2012-01-01 18.8854 2013-01-01 21.9657 2014-01-01 23.2350 2015-01-01 25.1211 2016-01-01 27.1489