Year Percent 1991-01-01 2.2000000000000000 1992-01-01 2.1120000000000000 1993-01-01 2.2260000000000000 1994-01-01 2.8528599999999997 1995-01-01 1.5600900000000000 1996-01-01 2.4060700000000000 1997-01-01 2.1698800000000000 1998-01-01 1.8758700000000001 1999-01-01 1.9924400000000002 2000-01-01 1.2962700000000000 2001-01-01 1.8145500000000000 2002-01-01 1.8954300000000000 2003-01-01 2.3132400000000000 2004-01-01 2.1282099999999997 2005-01-01 3.0030400000000000 2006-01-01 2.7538700000000000 2007-01-01 2.7478900000000000 2008-01-01 1.6649400000000000 2009-01-01 2.7585000000000000 2010-01-01 5.4719600000000000 2011-01-01 5.9875000000000000 2012-01-01 6.9090700000000000 2013-01-01 6.8730400000000000 2014-01-01 6.6063800000000010 2015-01-01 6.9482600000000000