Year Number 2004-01-01 15.65673326 2005-01-01 15.90035587 2006-01-01 18.00457467 2007-01-01 21.43816439 2008-01-01 23.98917781 2009-01-01 26.57668728 2010-01-01 34.47609598 2011-01-01 72.00175675 2012-01-01 85.70236439 2013-01-01 52.77793043 2014-01-01 59.02858087