Year Percent 1997-01-01 1.0038200000000002 1998-01-01 1.2305900000000000 1999-01-01 0.9873770000000001 2000-01-01 1.0832300000000000 2001-01-01 1.2188100000000000 2002-01-01 1.4529100000000001 2003-01-01 2.1667200000000000 2004-01-01 2.2258600000000000 2005-01-01 2.4489500000000000 2006-01-01 2.0851300000000000 2007-01-01 2.0851300000000000 2008-01-01 2.0851300000000000 2009-01-01 1.2947100000000000 2010-01-01 0.6683520000000001 2011-01-01 0.6194210000000000 2012-01-01 0.6586820000000000 2013-01-01 0.2588630000000000 2014-01-01 0.2572920000000000 2015-01-01 0.5042740000000000