Year Percent 1990-01-01 1.2686500000000000 1991-01-01 1.3684399999999999 1992-01-01 1.5106600000000001 1993-01-01 1.5415400000000000 1994-01-01 1.5229800000000000 1995-01-01 1.5054800000000000 1996-01-01 1.5872000000000000 1997-01-01 1.6466300000000000 1998-01-01 1.6223000000000000 1999-01-01 1.5561100000000000 2000-01-01 1.5607600000000001 2001-01-01 1.5637700000000000 2002-01-01 1.6572400000000000 2003-01-01 1.8922900000000002 2004-01-01 1.8629900000000001 2005-01-01 1.9123299999999999 2006-01-01 1.9280500000000000 2007-01-01 1.9329000000000000 2008-01-01 1.7345599999999999 2009-01-01 1.8762599999999998 2010-01-01 1.8772500000000000 2011-01-01 1.8535000000000000 2012-01-01 1.8520800000000000 2013-01-01 1.8397700000000001 2014-01-01 1.8447300000000000 2015-01-01 1.8315900000000000 2016-01-01 1.8351500000000000