Year Number 2004-01-01 9.2993 2005-01-01 9.4953 2006-01-01 9.7298 2007-01-01 10.0900 2008-01-01 10.3809 2009-01-01 10.2755 2010-01-01 10.1958 2011-01-01 9.9304 2012-01-01 9.5960 2013-01-01 9.1482 2014-01-01 8.9542 2015-01-01 8.9063 2016-01-01 8.7123 2017-01-01 8.4924