Year Number 2004-01-01 6.7100 2005-01-01 6.1663 2006-01-01 6.0067 2007-01-01 5.8551 2008-01-01 5.3749 2009-01-01 5.5725 2010-01-01 2.8788 2011-01-01 2.8095 2012-01-01 3.0434 2013-01-01 2.9655 2014-01-01 3.1784 2015-01-01 3.0975 2016-01-01 3.0182