Year Percent 1984-01-01 52.91790000000000 1985-01-01 57.37050000000000 1986-01-01 59.61600000000001 1987-01-01 57.27060000000000 1988-01-01 54.61540000000000 1989-01-01 58.30510000000000 1990-01-01 58.92030000000000 1991-01-01 61.44250000000000 1992-01-01 59.54110000000000 1993-01-01 69.72750000000000 1994-01-01 76.33830000000000 1995-01-01 74.33740000000000 1996-01-01 76.30860000000000 1997-01-01 81.53920000000000 1998-01-01 83.51730000000000 1999-01-01 81.43110000000000 2000-01-01 75.19870000000000 2001-01-01 68.95460000000000 2002-01-01 59.94540000000000 2003-01-01 51.71150000000000 2004-01-01 41.52450000000000 2005-01-01 42.01190000000000 2006-01-01 40.35420000000000 2007-01-01 41.40450000000000 2008-01-01 49.57380000000000 2009-01-01 56.03260000000000 2010-01-01 51.43320000000000 2011-01-01 50.79690000000000 2012-01-01 53.37500000000000 2013-01-01 55.24550000000000 2014-01-01 67.57600000000001 2015-01-01 100.83200000000001 2016-01-01 112.25399999999999