Year Percent 1982-01-01 15.678900000000000 1983-01-01 16.418200000000000 1984-01-01 15.833100000000000 1985-01-01 14.863400000000000 1986-01-01 15.494000000000002 1987-01-01 17.062800000000000 1988-01-01 19.501300000000000 1989-01-01 21.906400000000000 1990-01-01 22.404400000000000 1991-01-01 21.563300000000000 1992-01-01 22.036500000000000 1993-01-01 21.576600000000000 1994-01-01 22.887900000000000 1995-01-01 20.342700000000000 1996-01-01 21.487700000000000 1997-01-01 20.528900000000000 1998-01-01 18.509400000000000 1999-01-01 18.020700000000000 2000-01-01 18.352600000000000 2001-01-01 20.973900000000000 2002-01-01 23.389600000000000 2003-01-01 22.518200000000000 2004-01-01 21.421900000000000 2005-01-01 20.943300000000000 2006-01-01 22.988500000000000 2007-01-01 24.954500000000000 2008-01-01 25.375000000000000 2009-01-01 27.422400000000000 2010-01-01 31.208000000000002 2011-01-01 32.732000000000000 2012-01-01 36.172500000000000 2013-01-01 35.611999999999995 2014-01-01 40.051800000000000 2015-01-01 42.103200000000000 2016-01-01 46.010600000000000