Year Number 2004-01-01 12.2900 2005-01-01 12.5047 2006-01-01 12.6353 2007-01-01 20.7540 2008-01-01 23.4882 2009-01-01 26.1851 2010-01-01 27.6316 2011-01-01 29.1620 2012-01-01 30.5244 2013-01-01 31.6909 2014-01-01 32.4188 2015-01-01 33.2587 2016-01-01 33.2027 2017-01-01 33.3333