Month Millions of Dollars 2007-01-01 3.982735000000000 2007-02-01 4.114561999999999 2007-03-01 7.331147000000000 2007-04-01 16.024817999999996 2007-05-01 7.875513999999998 2007-06-01 13.607189000000000 2007-07-01 10.093199000000000 2007-08-01 8.020426000000000 2007-09-01 9.997021000000000 2007-10-01 7.748689000000000 2007-11-01 10.797856000000000 2007-12-01 9.989934000000000 2008-01-01 9.099345000000000 2008-02-01 19.674576000000000 2008-03-01 10.616067000000003 2008-04-01 17.461337000000000 2008-05-01 30.471086000000007 2008-06-01 19.860194000000003 2008-07-01 23.772442000000000 2008-08-01 18.911274000000000 2008-09-01 24.037205000000000 2008-10-01 12.489172000000000 2008-11-01 10.986050999999998 2008-12-01 9.978709000000002