Year Percent 1999-12-31 3.4457 2000-12-31 4.4024 2001-12-31 4.2693 2002-12-31 3.3189 2003-12-31 2.3309 2004-12-31 2.1066 2005-12-31 2.184 2006-12-31 3.0807 2007-12-31 4.2765 2008-12-31 4.6418 2009-12-31 1.222 2010-12-31 0.8135 2011-12-31 1.3942 2012-12-31 0.5711 2013-12-31 0.2205 2014-12-31 0.2082 2015-12-31 -0.0197 2016-12-31 -0.2645 2017-12-31 -0.3291 2018-12-31 -0.3221 2019-12-31 -0.3571 2020-12-31 -0.4274