Year Number 2004-01-01 7.519472475 2005-01-01 12.351711560 2006-01-01 14.123080740 2007-01-01 14.051333750 2008-01-01 14.520151830 2009-01-01 10.680149810 2010-01-01 8.685262587 2011-01-01 6.341904517 2012-01-01 6.375013886 2013-01-01 6.003126430 2014-01-01 4.822184863