Year Number 2004-01-01 3.8463 2005-01-01 4.2811 2006-01-01 4.8699 2007-01-01 7.8529 2008-01-01 8.8783 2009-01-01 8.9702 2010-01-01 9.0834 2011-01-01 6.1744 2012-01-01 6.6974 2013-01-01 6.8702 2014-01-01 6.3107 2015-01-01 6.5616 2016-01-01 6.7626 2017-01-01 7.1184