Year Percent 1980-01-01 7.4049600000000010 1981-01-01 7.5214300000000005 1982-01-01 8.0592800000000010 1983-01-01 8.3840200000000000 1984-01-01 8.8156000000000000 1985-01-01 10.2119000000000000 1986-01-01 12.4748000000000000 1987-01-01 15.7156000000000000 1988-01-01 16.4142000000000000 1989-01-01 16.0946000000000000 1990-01-01 12.8941000000000000 1991-01-01 11.6338000000000000 1992-01-01 8.9916900000000000 1993-01-01 7.9672899999999990 1994-01-01 7.2445200000000000 1995-01-01 6.0098500000000000 1996-01-01 7.3610800000000000 1997-01-01 11.2945000000000000 1998-01-01 17.3840000000000000 1999-01-01 18.0492000000000000 2000-01-01 21.1908000000000000 2001-01-01 21.7522000000000000 2002-01-01 23.1757000000000000 2003-01-01 26.7955000000000000 2004-01-01 28.1942000000000000 2005-01-01 24.9395000000000000 2006-01-01 31.5046000000000000 2007-01-01 34.8472000000000000 2008-01-01 35.3206000000000000 2009-01-01 46.6147000000000000 2010-01-01 45.9358000000000000 2011-01-01 46.7322000000000000 2012-01-01 51.5178000000000000 2013-01-01 53.7291000000000000 2014-01-01 51.4139999999999940 2015-01-01 60.2432000000000000