Year Number 2004-01-01 15.4240 2005-01-01 16.9678 2006-01-01 18.8175 2007-01-01 20.9096 2008-01-01 29.3683 2009-01-01 31.1761 2010-01-01 32.5527 2011-01-01 41.1439 2012-01-01 40.6242 2013-01-01 44.5894 2014-01-01 50.0426 2015-01-01 65.7269 2016-01-01 48.4741 2017-01-01 55.0431