Year Number 2004-01-01 14.0635 2005-01-01 14.9097 2006-01-01 16.7254 2007-01-01 19.1327 2008-01-01 20.3761 2009-01-01 22.0904 2010-01-01 25.4684 2011-01-01 29.0813 2012-01-01 33.1781 2013-01-01 53.6207 2014-01-01 54.5142 2015-01-01 51.4578 2016-01-01 53.7571