Year Percent 1982-01-01 1.6173799999999998 1983-01-01 1.5615000000000000 1984-01-01 1.7116900000000002 1985-01-01 2.0242600000000000 1986-01-01 2.1796700000000000 1987-01-01 2.1707500000000000 1988-01-01 2.3755599999999997 1989-01-01 2.7241000000000000 1990-01-01 2.6800900000000003 1991-01-01 2.9303400000000000 1992-01-01 3.3530300000000004 1993-01-01 3.2778300000000002 1994-01-01 4.5028500000000000 1995-01-01 4.2029700000000000 1996-01-01 4.0358700000000000 1997-01-01 3.8859300000000000 1998-01-01 3.9395400000000000 1999-01-01 3.7584400000000002 2000-01-01 3.5842099999999997 2001-01-01 3.0034500000000000 2002-01-01 2.7339800000000000 2003-01-01 2.6638200000000000 2004-01-01 2.3795000000000000 2005-01-01 2.5171400000000000 2006-01-01 3.2146300000000000 2007-01-01 3.5538900000000000 2008-01-01 3.7822199999999997 2009-01-01 4.4346000000000000 2010-01-01 5.2401700000000000 2011-01-01 5.7715100000000000 2012-01-01 6.1445099999999995 2013-01-01 6.0217100000000000 2014-01-01 6.8364300000000000 2015-01-01 5.5510800000000010 2016-01-01 5.6413800000000010