Year Number 2004-01-01 14.19544986 2005-01-01 14.93665424 2006-01-01 14.44194561 2007-01-01 13.19884874 2008-01-01 14.97297661 2009-01-01 15.33838763 2010-01-01 16.42965720 2011-01-01 17.62667938 2012-01-01 18.90195375