Year Percent 1990-01-01 1.4560500000000000 1991-01-01 1.5912100000000000 1992-01-01 1.7224300000000000 1993-01-01 2.0349100000000000 1994-01-01 2.2237900000000000 1995-01-01 2.7054300000000000 1996-01-01 2.9125200000000000 1997-01-01 7.4228399999999990 1998-01-01 8.1318700000000000 1999-01-01 7.2066300000000005 2000-01-01 6.8561500000000000 2001-01-01 7.0464899999999995 2002-01-01 7.3814400000000000 2003-01-01 6.7835000000000000 2004-01-01 6.1861800000000000 2005-01-01 5.8671600000000000 2006-01-01 5.2141500000000000 2007-01-01 5.0068699999999990 2008-01-01 4.9609800000000000 2009-01-01 5.0088500000000000 2010-01-01 4.9749700000000000 2011-01-01 4.9409100000000000 2012-01-01 4.9848900000000000 2013-01-01 5.1381900000000000 2014-01-01 5.0340800000000000 2015-01-01 4.6838600000000000 2016-01-01 4.5765100000000000