Year Number 2004-01-01 3.9026 2005-01-01 6.2456 2006-01-01 8.4856 2007-01-01 11.7355 2008-01-01 14.0720 2009-01-01 16.8097 2010-01-01 21.3989 2011-01-01 25.9095 2012-01-01 30.3989 2013-01-01 57.9979 2014-01-01 58.5012 2015-01-01 65.3102 2016-01-01 69.0145 2017-01-01 71.3778