Year Percent 1990-01-01 2.8217600000000000 1991-01-01 2.8867300000000000 1992-01-01 2.9134700000000002 1993-01-01 2.8456700000000000 1994-01-01 2.9412400000000000 1995-01-01 2.8693500000000000 1996-01-01 3.0104700000000000 1997-01-01 3.1523500000000000 1998-01-01 3.5634200000000000 1999-01-01 4.3047200000000000 2000-01-01 5.3226600000000000 2001-01-01 4.9031699999999990 2002-01-01 4.3902500000000000 2003-01-01 4.0862300000000005 2004-01-01 3.8992600000000000 2005-01-01 4.4253000000000000 2006-01-01 4.6142100000000000 2007-01-01 4.9120800000000004 2008-01-01 5.0304699999999990 2009-01-01 5.8799000000000000 2010-01-01 6.0166400000000000 2011-01-01 5.7355500000000000 2012-01-01 5.0117199999999995 2013-01-01 5.3309500000000000 2014-01-01 4.9719200000000000 2015-01-01 5.3091900000000000 2016-01-01 6.4609900000000000