Year Number 2004-01-01 1.66835792944193 2005-01-01 1.72942017978698 2006-01-01 1.79364361694836 2007-01-01 1.85696492294821 2008-01-01 1.87314884163390 2009-01-01 1.84855019240716 2010-01-01 1.88820801767572 2011-01-01 1.86649401817956 2012-01-01 1.89135334433961 2013-01-01 2.03132145064539 2014-01-01 1.88325230307532