Year Number 2004-01-01 0.6027 2005-01-01 0.9539 2006-01-01 1.1860 2007-01-01 2.3652 2008-01-01 4.6714 2009-01-01 8.3445 2010-01-01 7.3316 2011-01-01 11.9135 2012-01-01 15.5801 2013-01-01 20.5628 2014-01-01 24.7027 2015-01-01 30.1144 2016-01-01 31.2070 2017-01-01 33.9197