Year Number 2004-01-01 2.7970 2005-01-01 6.6714 2006-01-01 10.0942 2007-01-01 20.6342 2008-01-01 23.7675 2009-01-01 14.7013 2010-01-01 17.3503 2011-01-01 20.3933 2012-01-01 24.5201 2013-01-01 32.8475