Year Number 2004-01-01 9.1811 2005-01-01 10.9181 2006-01-01 14.8883 2007-01-01 21.0918 2008-01-01 27.0471 2009-01-01 30.2730 2010-01-01 34.9876 2011-01-01 37.4690 2012-01-01 40.1985 2013-01-01 40.4467 2014-01-01 42.4318 2015-01-01 41.9355 2016-01-01 42.4318