Year Number 2004-01-01 16.2341 2005-01-01 22.8179 2006-01-01 32.4338 2007-01-01 45.0168 2008-01-01 61.6050 2009-01-01 72.3899 2010-01-01 95.5444 2011-01-01 116.8919 2012-01-01 142.0036 2013-01-01 156.5062 2014-01-01 185.3242 2015-01-01 172.6046 2016-01-01 168.6977