Year Number 2004-01-01 30.0013 2005-01-01 33.8948 2006-01-01 37.0746 2007-01-01 41.9110 2008-01-01 31.7820 2009-01-01 26.5474 2010-01-01 39.8673 2011-01-01 63.9710 2012-01-01 61.1237 2013-01-01 67.2657 2014-01-01 72.3148 2015-01-01 84.1619 2016-01-01 77.8293 2017-01-01 79.5845