Year Percent 1991-01-01 0.7356420000000000 1992-01-01 0.8017860000000000 1993-01-01 0.9425280000000000 1994-01-01 1.0959200000000000 1995-01-01 1.2661500000000000 1996-01-01 1.3409799999999998 1997-01-01 1.8158800000000000 1998-01-01 2.4282500000000000 1999-01-01 3.1430800000000000 2000-01-01 3.3167000000000000 2001-01-01 3.6895900000000000 2002-01-01 4.2478600000000000 2003-01-01 4.6755900000000010 2004-01-01 4.7002100000000000 2005-01-01 5.1124300000000010 2006-01-01 4.6413199999999994 2007-01-01 3.9537699999999996 2008-01-01 3.4649300000000003 2009-01-01 5.3408900000000000 2010-01-01 5.8117100000000000 2011-01-01 4.6741800000000010 2012-01-01 4.4491700000000000 2013-01-01 5.4544300000000000 2014-01-01 6.8356699999999995 2015-01-01 6.9901200000000000 2016-01-01 6.1111100000000000