Quarter Billions of US Dollars 1997-01-01 0.22873 1997-04-01 0.22873 1997-07-01 0.22873 1997-10-01 0.22873 1998-01-01 0.22873 1998-04-01 0.22873 1998-07-01 0.22873 1998-10-01 0.22873 1999-01-01 0.22873 1999-04-01 0.22873 1999-07-01 0.22873 1999-10-01 0.22873 2000-01-01 0.22873 2000-04-01 0.22873 2000-07-01 0.22873 2000-10-01 0.22873 2001-01-01 0.22873 2001-04-01 0.22873 2001-07-01 0.22873 2001-10-01 0.22873 2002-01-01 0.22530 2002-04-01 0.22530 2002-07-01 0.22187 2002-10-01 0.22187 2003-01-01 0.21730 2003-04-01 0.21730 2003-07-01 0.21273 2003-10-01 0.21273 2004-01-01 0.20816 2004-04-01 0.20816 2004-07-01 0.20359 2004-10-01 0.20359 2005-01-01 0.19902 2005-04-01 0.19902 2005-07-01 0.19445 2005-10-01 0.37140 2006-01-01 0.36915 2006-04-01 0.37828 2006-07-01 0.37063 2006-10-01 0.37828 2007-01-01 0.37364 2007-04-01 0.37644 2007-07-01 0.37969 2007-10-01 0.38782 2008-01-01 0.39390 2008-04-01 0.39318 2008-07-01 0.36097 2008-10-01 0.35518 2009-01-01 0.33004 2009-04-01 0.34243 2009-07-01 0.59030 2009-10-01 0.58260 2010-01-01 0.53646 2010-04-01 0.49720 2010-07-01 0.52595 2010-10-01 0.51665 2011-01-01 0.52352 2011-04-01 0.53152 2011-07-01 0.48004 2011-10-01 0.46171 2012-01-01 0.45467 2012-04-01 0.42977 2012-07-01 0.42023 2012-10-01 0.42881 2013-01-01 0.19207 2013-04-01 0.19620 2013-07-01 0.20258 2013-10-01 0.20686 2014-01-01 0.20682 2014-04-01 0.20487 2014-07-01 0.81790 2014-10-01 0.78917 2015-01-01 0.69934 2015-04-01 0.72728