Year Percent 1975-01-01 17.85060000000000 1976-01-01 17.62640000000000 1977-01-01 17.77930000000000 1978-01-01 16.98800000000000 1979-01-01 16.33890000000000 1980-01-01 15.41240000000000 1981-01-01 14.08040000000000 1982-01-01 14.82960000000000 1983-01-01 19.02390000000000 1984-01-01 23.08410000000000 1985-01-01 33.00760000000000 1986-01-01 41.32480000000000 1987-01-01 38.73810000000000 1988-01-01 38.11070000000000 1989-01-01 49.84230000000000 1990-01-01 47.92140000000000 1991-01-01 44.15200000000000 1992-01-01 49.12310000000000 1993-01-01 49.42320000000000 1994-01-01 55.02200000000000 1995-01-01 60.78670000000000 1996-01-01 73.00980000000000 1997-01-01 96.32370000000000 1998-01-01 123.22600000000000 1999-01-01 144.57200000000000 2000-01-01 150.98500000000000 2001-01-01 133.82200000000000 2002-01-01 101.22500000000000 2003-01-01 85.61030000000000 2004-01-01 83.39920000000000 2005-01-01 84.17360000000000 2006-01-01 95.21480000000000 2007-01-01 108.32700000000001 2008-01-01 76.71260000000000 2009-01-01 54.52990000000000 2010-01-01 71.82420000000000 2011-01-01 72.78570000000000 2012-01-01 72.81530000000000 2013-01-01 86.69580000000000 2014-01-01 91.81470000000000 2015-01-01 91.97170000000000 2016-01-01 98.64700000000000 2017-01-01 116.56600000000000