Year Percent 1987-01-01 1.2499100000000000 1988-01-01 1.0913100000000000 1989-01-01 1.0485799999999998 1990-01-01 1.2561200000000001 1991-01-01 1.2911800000000000 1992-01-01 1.1250799999999999 1993-01-01 1.3752300000000000 1994-01-01 2.2008500000000000 1995-01-01 1.7868400000000002 1996-01-01 1.6583100000000000 1997-01-01 1.8648600000000000 1998-01-01 1.7494800000000000 1999-01-01 1.6703700000000001 2000-01-01 1.4871600000000000 2001-01-01 1.3767700000000000 2002-01-01 1.2499000000000000 2003-01-01 1.2559900000000000 2004-01-01 1.2802200000000001 2005-01-01 1.1987100000000000 2006-01-01 1.0491000000000000 2007-01-01 1.1096200000000000 2008-01-01 1.0180700000000000 2009-01-01 0.9152680000000001 2010-01-01 1.1635400000000000 2011-01-01 1.5609600000000001 2012-01-01 2.0155400000000000 2013-01-01 2.8365000000000000 2014-01-01 4.1231200000000000 2015-01-01 4.6906400000000000 2016-01-01 5.6636900000000000