Year Percent 1977-01-01 0.23319099999999998 1978-01-01 0.21285700000000002 1979-01-01 0.18779000000000000 1980-01-01 0.24316300000000002 1981-01-01 0.25015300000000000 1982-01-01 0.24892899999999998 1983-01-01 0.46251499999999995 1984-01-01 1.73669000000000000 1985-01-01 3.03852000000000000 1986-01-01 3.75745000000000000 1987-01-01 6.26924000000000000 1988-01-01 8.44679000000000000 1989-01-01 7.24421999999999900 1990-01-01 4.67724000000000000 1991-01-01 3.45800000000000000 1992-01-01 2.50644000000000000 1993-01-01 5.33577000000000000 1994-01-01 8.17063999999999900 1995-01-01 9.73305000000000000 1996-01-01 10.41830000000000000 1997-01-01 12.74970000000000000 1998-01-01 13.79400000000000000 1999-01-01 17.83780000000000000 2000-01-01 24.91840000000000000 2001-01-01 35.73300000000000400 2002-01-01 44.38620000000000000 2003-01-01 54.33000000000000000 2004-01-01 56.65070000000000000 2005-01-01 56.44170000000000000 2006-01-01 73.15970000000000000 2007-01-01 80.78510000000000000 2008-01-01 76.95620000000000000 2009-01-01 104.91100000000000000 2010-01-01 96.65410000000000000 2011-01-01 84.91470000000000000 2012-01-01 85.59020000000000000 2013-01-01 79.51440000000000000 2014-01-01 59.78360000000000000 2015-01-01 57.42750000000000000 2016-01-01 49.39410000000000000