Year Number 2004-01-01 3.2726 2005-01-01 7.2329 2006-01-01 10.8640 2007-01-01 21.7821 2008-01-01 26.1359 2009-01-01 16.0218 2010-01-01 18.4948 2011-01-01 21.4724 2012-01-01 25.6899 2013-01-01 34.2225