Year Number 2004-01-01 3.1831 2005-01-01 3.3258 2006-01-01 3.9540 2007-01-01 4.3807 2008-01-01 7.4164 2009-01-01 8.0869 2010-01-01 10.3849 2011-01-01 10.4267 2012-01-01 14.3439