Year Percent 1980-01-01 1.6455000000000000 1981-01-01 1.7307800000000000 1982-01-01 2.1126200000000000 1983-01-01 2.4488900000000000 1984-01-01 1.9445000000000000 1985-01-01 1.6686700000000000 1986-01-01 2.0798000000000000 1987-01-01 1.6802099999999998 1988-01-01 1.0962399999999999 1989-01-01 0.7670510000000000 1990-01-01 12.8901000000000000 1991-01-01 11.7581000000000000 1992-01-01 11.2530000000000000 1993-01-01 11.1992000000000000 1994-01-01 11.8346000000000000 1995-01-01 15.3998000000000000 1996-01-01 16.4120000000000000 1997-01-01 14.2897000000000000 1998-01-01 13.7927000000000000 1999-01-01 13.8702000000000000 2000-01-01 12.1079999999999990 2001-01-01 10.8864000000000000 2002-01-01 10.4319000000000000 2003-01-01 9.8713900000000000 2004-01-01 10.0747000000000000 2005-01-01 9.3567300000000000 2006-01-01 8.5595400000000000 2007-01-01 8.3374300000000000 2008-01-01 7.2158700000000000 2009-01-01 10.2053000000000000 2010-01-01 9.5252900000000000 2011-01-01 9.9305000000000000 2012-01-01 11.9647000000000000 2013-01-01 13.4297000000000000 2014-01-01 14.5209000000000000 2015-01-01 17.8409999999999980 2016-01-01 22.3419000000000000