Year Number 2004-01-01 2.3387 2005-01-01 2.6952 2006-01-01 3.2442 2007-01-01 3.1162 2008-01-01 3.1910 2009-01-01 3.3753 2010-01-01 5.2189 2011-01-01 5.8126 2012-01-01 10.3346 2013-01-01 12.1854 2014-01-01 12.4927 2015-01-01 14.4636