Year Number 2008-01-01 11.1948 2009-01-01 13.9991 2010-01-01 16.4857 2011-01-01 19.7895 2012-01-01 20.4405 2013-01-01 39.2271 2014-01-01 43.9683 2015-01-01 38.4864 2016-01-01 42.3291