Year Percent 1989-01-01 6.21051 1990-01-01 10.72270 1991-01-01 12.47530 1992-01-01 9.48011 1993-01-01 9.18490 1994-01-01 11.28720 1995-01-01 11.84320 1996-01-01 13.79370 1997-01-01 19.21000 1998-01-01 38.25460 1999-01-01 96.20580 2000-01-01 109.89000 2001-01-01 60.86670 2002-01-01 50.73350 2003-01-01 46.21710 2004-01-01 50.30030 2005-01-01 54.52210 2006-01-01 63.30280 2007-01-01 75.41120 2008-01-01 53.31630 2009-01-01 29.83960 2010-01-01 29.49370 2011-01-01 18.24970 2012-01-01 15.44240 2013-01-01 26.76570 2014-01-01 29.02160 2015-01-01 22.50970 2016-01-01 20.34410 2017-01-01 22.04140