Year Number 2005-01-01 15.2454 2006-01-01 22.7296 2007-01-01 31.6515 2008-01-01 32.3426 2009-01-01 29.9454 2010-01-01 31.6612 2011-01-01 31.4594 2012-01-01 32.4102 2013-01-01 34.3619 2014-01-01 35.6258 2015-01-01 37.4918 2016-01-01 36.4136