Year Percent 1980-01-01 1.2368900000000000 1981-01-01 1.3446799999999999 1982-01-01 1.6136600000000000 1983-01-01 1.9022500000000000 1984-01-01 1.5020300000000000 1985-01-01 1.3289600000000001 1986-01-01 1.6784400000000002 1987-01-01 1.4271500000000000 1988-01-01 0.9713440000000001 1989-01-01 0.6682150000000000 1990-01-01 1.6044500000000000 1991-01-01 1.9200500000000000 1992-01-01 2.5742599999999998 1993-01-01 3.9700500000000000 1994-01-01 4.8858900000000000 1995-01-01 5.5297300000000010 1996-01-01 4.7567100000000000 1997-01-01 4.5601699999999990 1998-01-01 4.5169000000000000 1999-01-01 4.7551700000000000 2000-01-01 4.3192400000000000 2001-01-01 4.1479300000000010 2002-01-01 3.8664600000000000 2003-01-01 4.2593100000000000 2004-01-01 4.4245100000000000 2005-01-01 4.4145800000000000 2006-01-01 4.2700700000000000 2007-01-01 4.3889600000000000 2008-01-01 3.6461699999999997 2009-01-01 5.4953900000000000 2010-01-01 5.3234800000000000 2011-01-01 6.0525400000000005 2012-01-01 7.8595399999999990 2013-01-01 9.2242000000000000 2014-01-01 10.1854000000000000 2015-01-01 12.5036000000000000 2016-01-01 16.0621000000000000