Year Number 2004-01-01 9.7562 2005-01-01 13.1894 2006-01-01 13.2610 2007-01-01 15.9807 2008-01-01 19.7173 2009-01-01 20.2437 2010-01-01 20.4570 2011-01-01 21.1019 2012-01-01 21.4521 2013-01-01 24.0448 2014-01-01 33.7114 2015-01-01 31.1567 2016-01-01 28.8129 2017-01-01 43.6439