Year Percent 1982-01-01 47.98140000000000 1983-01-01 47.60910000000000 1984-01-01 46.12830000000000 1985-01-01 46.63420000000000 1986-01-01 47.86190000000000 1987-01-01 46.63770000000000 1988-01-01 43.19690000000000 1989-01-01 39.51390000000000 1990-01-01 40.89810000000000 1991-01-01 43.22830000000000 1992-01-01 47.70390000000000 1993-01-01 50.58330000000000 1994-01-01 46.78610000000000 1995-01-01 43.97340000000000 1996-01-01 43.59910000000000 1997-01-01 42.24460000000000 1998-01-01 41.95080000000000 1999-01-01 43.20110000000000 2000-01-01 42.73350000000000 2001-01-01 42.63890000000000 2002-01-01 43.12630000000000 2003-01-01 44.29320000000000 2004-01-01 44.95399999999999 2005-01-01 46.39620000000000 2006-01-01 48.60950000000000 2007-01-01 51.79950000000000 2008-01-01 53.90500000000000 2009-01-01 59.59560000000000 2010-01-01 60.68880000000000 2011-01-01 61.29910000000000 2012-01-01 61.51560000000000 2013-01-01 58.78210000000000 2014-01-01 57.33650000000000 2015-01-01 56.63410000000000 2016-01-01 57.90220000000000