Year Percent 1989-01-01 29.343800000000000 1990-01-01 27.661200000000000 1991-01-01 26.382200000000000 1992-01-01 25.066999999999997 1993-01-01 26.593900000000000 1994-01-01 27.569000000000003 1995-01-01 27.157500000000000 1996-01-01 24.235100000000000 1997-01-01 25.776999999999997 1998-01-01 26.260900000000000 1999-01-01 23.706800000000000 2000-01-01 23.861700000000000 2001-01-01 22.455300000000000 2002-01-01 25.279100000000000 2003-01-01 24.043300000000000 2004-01-01 24.020000000000000 2005-01-01 20.296800000000000 2006-01-01 20.160000000000000 2007-01-01 18.747900000000000 2008-01-01 17.727600000000000 2009-01-01 17.859200000000000 2010-01-01 18.627400000000000 2011-01-01 15.873800000000000 2012-01-01 16.872000000000000 2013-01-01 16.676100000000000 2014-01-01 14.461400000000000 2015-01-01 14.223300000000000 2016-01-01 13.481400000000000