Quarter Billions of US Dollars 2002-01-01 0.140 2004-04-01 0.100 2006-07-01 0.125 2009-07-01 -0.075 2010-04-01 -0.140 2010-07-01 0.020 2011-07-01 -0.150 2012-07-01 -0.020 2015-04-01 0.300