Year Percent 1980-01-01 7.226360000000001 1981-01-01 8.206910000000000 1982-01-01 9.627110000000000 1983-01-01 9.477160000000001 1984-01-01 9.646000000000000 1985-01-01 10.241900000000000 1986-01-01 11.845100000000000 1987-01-01 11.515400000000000 1988-01-01 10.819900000000000 1989-01-01 10.355300000000000 1990-01-01 10.441200000000000 1991-01-01 11.253500000000000 1992-01-01 11.289400000000000 1993-01-01 12.171700000000000 1994-01-01 12.556800000000000 1995-01-01 12.208100000000000 1996-01-01 12.221200000000000 1997-01-01 12.847100000000000 1998-01-01 15.517999999999999 1999-01-01 15.972700000000000 2000-01-01 14.453500000000000 2001-01-01 17.398400000000000 2002-01-01 18.589200000000000 2003-01-01 19.337700000000000 2004-01-01 19.357200000000000 2005-01-01 18.226100000000000 2006-01-01 19.336300000000000 2007-01-01 23.162100000000000 2008-01-01 23.681500000000000 2009-01-01 31.699800000000000 2010-01-01 30.550900000000000 2011-01-01 29.307600000000000 2012-01-01 30.804100000000000 2013-01-01 33.653100000000000 2014-01-01 35.023500000000000 2015-01-01 41.628200000000000 2016-01-01 46.393700000000000