Year Number 2004-01-01 9.81266826214496 2005-01-01 15.67058023078420 2006-01-01 12.77788391792310 2007-01-01 18.86607579817020 2008-01-01 19.19400918237840 2009-01-01 24.49721192333040 2010-01-01 20.43929292873000 2011-01-01 13.47565857689200 2012-01-01 14.29007616976450 2013-01-01 13.97922981283200 2014-01-01 12.76092606968670