Year Percent 1987-01-01 883.40400000000000 1988-01-01 345.88599999999997 1989-01-01 5.91211000000000 1990-01-01 5.91211000000000 1991-01-01 5.91211000000000 1992-01-01 18.85630000000000 1993-01-01 17.35850000000000 1994-01-01 15.53270000000000 1995-01-01 15.08710000000000 1996-01-01 12.89500000000000 1997-01-01 12.34960000000000 1998-01-01 12.72170000000000 1999-01-01 13.74550000000000 2000-01-01 17.48090000000000 2001-01-01 16.06270000000000 2002-01-01 17.11590000000000 2003-01-01 19.62310000000000 2004-01-01 18.55540000000000 2005-01-01 17.68870000000000 2006-01-01 21.13580000000000 2007-01-01 20.02580000000000 2008-01-01 22.72330000000000 2009-01-01 26.81150000000000 2010-01-01 30.42620000000000 2011-01-01 31.68860000000000 2012-01-01 33.23790000000000 2013-01-01 37.28760000000000 2014-01-01 40.40050000000000 2015-01-01 44.27370000000000 2016-01-01 45.50560000000000