Year Number 2004-01-01 0.6803 2005-01-01 0.7170 2006-01-01 0.9744 2007-01-01 1.8202 2008-01-01 2.4637 2009-01-01 2.6475 2010-01-01 2.8498 2011-01-01 3.0888 2012-01-01 3.1991 2013-01-01 3.3646 2014-01-01 3.7139 2015-01-01 4.1184 2016-01-01 4.5413