Year Percent 1981-01-01 11.81469755002120 1982-01-01 9.82116244432080 1983-01-01 13.50251051701790 1984-01-01 20.02630320423250 1985-01-01 10.51897599371660 1986-01-01 14.04686795876440 1987-01-01 25.15509542829110 1988-01-01 33.91216493543390 1989-01-01 12.44636205026640 1990-01-01 11.82353804541510 1991-01-01 12.61531538288490 1992-01-01 23.75135302303980 1993-01-01 22.77271023366250 1994-01-01 34.64963615083230 1995-01-01 83.32577475434590 1996-01-01 37.60204502350160 1997-01-01 9.13735243003495 1998-01-01 29.74865128282630 1999-01-01 44.80416428616740 2000-01-01 29.58148846316840 2001-01-01 22.70000000000000 2002-01-01 14.74463461016030 2003-01-01 9.57679786919213 2004-01-01 11.42980608221240 2005-01-01 15.41034466042960 2006-01-01 13.97429435483880 2007-01-01 7.95220990864032 2008-01-01 8.71260186609040 2009-01-01 8.42204427696655 2010-01-01 7.41159092883827 2011-01-01 7.62282262848512 2012-01-01 21.27126500137800 2013-01-01 27.28333333333330 2014-01-01 23.79206494696870 2015-01-01 21.86734755425530 2016-01-01 21.71111321364990 2017-01-01 12.17842434615180