Year Percent 1984-01-01 52.91790000000000 1985-01-01 57.37050000000000 1986-01-01 59.14720000000000 1987-01-01 56.49240000000000 1988-01-01 54.02140000000000 1989-01-01 57.93260000000000 1990-01-01 58.33520000000000 1991-01-01 60.64050000000000 1992-01-01 58.88590000000000 1993-01-01 69.17040000000000 1994-01-01 75.97650000000000 1995-01-01 74.13950000000000 1996-01-01 76.24390000000000 1997-01-01 81.53890000000000 1998-01-01 83.51500000000000 1999-01-01 81.42900000000000 2000-01-01 75.19870000000000 2001-01-01 67.65960000000000 2002-01-01 57.05500000000000 2003-01-01 48.70800000000000 2004-01-01 39.22870000000000 2005-01-01 39.99730000000000 2006-01-01 38.69250000000000 2007-01-01 40.07260000000000 2008-01-01 48.39130000000000 2009-01-01 54.86150000000000 2010-01-01 50.49140000000000 2011-01-01 50.08250000000000 2012-01-01 53.06810000000000 2013-01-01 55.24300000000000 2014-01-01 67.57580000000000 2015-01-01 100.83100000000000 2016-01-01 112.25399999999999