Year Number 2004-01-01 5.596770737 2005-01-01 5.868094354 2006-01-01 6.565729787 2007-01-01 6.589351422 2008-01-01 7.304474237 2009-01-01 7.402513983 2010-01-01 7.861777691 2011-01-01 8.863261011 2012-01-01 9.594959621 2013-01-01 9.432952843 2014-01-01 9.281562359