Year Percent 1980-01-01 1.40983000000000000 1981-01-01 1.39123000000000000 1982-01-01 1.29041000000000000 1983-01-01 1.19713999999999990 1984-01-01 1.04542000000000000 1985-01-01 1.27732999999999990 1986-01-01 0.99467199999999990 1987-01-01 0.89659000000000000 1988-01-01 0.54666100000000000 1989-01-01 0.37358600000000003 1990-01-01 1.81453000000000000 1991-01-01 1.65012000000000000 1992-01-01 6.99308000000000000 1993-01-01 7.01380000000000000 1994-01-01 6.05807000000000000 1995-01-01 5.17845000000000000 1996-01-01 5.60084000000000000 1997-01-01 5.53291000000000000 1998-01-01 7.43637000000000000 1999-01-01 9.98590000000000000 2000-01-01 11.31250000000000000 2001-01-01 13.07070000000000000 2002-01-01 15.65380000000000000 2003-01-01 18.78100000000000000 2004-01-01 19.02620000000000000 2005-01-01 18.94850000000000000 2006-01-01 17.81430000000000000 2007-01-01 14.98299999999999900 2008-01-01 12.76720000000000000 2009-01-01 14.56360000000000000 2010-01-01 13.24120000000000000 2011-01-01 12.17120000000000000 2012-01-01 11.75840000000000000 2013-01-01 10.09850000000000000 2014-01-01 9.64063000000000000 2015-01-01 9.78251000000000000 2016-01-01 9.35702000000000000