Year Number 2004-01-01 5.6001 2005-01-01 7.4228 2006-01-01 9.8913 2007-01-01 11.7952 2008-01-01 14.1457 2009-01-01 15.7869 2010-01-01 17.4617 2011-01-01 20.1986 2012-01-01 23.0816 2013-01-01 27.3032 2014-01-01 30.4717 2015-01-01 33.4431 2016-01-01 37.2440