{"pre_text": ["supplementary information on oil and gas producing activities ( unaudited ) c o n t i n u e d summary of changes in standardized measure of discounted future net cash flows relating to proved oil and gas reserves ( in millions ) 2006 2005 2004 sales and transfers of oil and gas produced , net of production , transportation and administrative costs $ ( 5312 ) $ ( 3754 ) $ ( 2689 ) net changes in prices and production , transportation and administrative costs related to future production ( 1342 ) 6648 771 ."], "post_text": ["."], "table": [["( in millions )", "2006", "2005", "2004"], ["sales and transfers of oil and gas produced net of production transportation and administrative costs", "$ -5312 ( 5312 )", "$ -3754 ( 3754 )", "$ -2689 ( 2689 )"], ["net changes in prices and production transportation and administrative costs related to future production", "-1342 ( 1342 )", "6648", "771"], ["extensions discoveries and improved recovery less related costs", "1290", "700", "1349"], ["development costs incurred during the period", "1251", "1030", "609"], ["changes in estimated future development costs", "-527 ( 527 )", "-552 ( 552 )", "-628 ( 628 )"], ["revisions of previous quantity estimates", "1319", "820", "948"], ["net changes in purchases and sales of minerals in place", "30", "4557", "33"], ["accretion of discount", "1882", "1124", "757"], ["net change in income taxes", "-660 ( 660 )", "-6694 ( 6694 )", "-627 ( 627 )"], ["timing and other", "-14 ( 14 )", "307", "97"], ["net change for the year", "-2083 ( 2083 )", "4186", "620"], ["beginning of year", "10601", "6415", "5795"], ["end of year", "$ 8518", "$ 10601", "$ 6415"], ["net change for the year from discontinued operations", "$ -216 ( 216 )", "$ 162", "$ -152 ( 152 )"]], "table_ori": [["<i>(In millions)</i>", "2006", "2005", "2004"], ["Sales and transfers of oil and gas produced, net of production, transportation and administrative costs", "$(5,312)", "$(3,754)", "$(2,689)"], ["Net changes in prices and production, transportation and administrative costs related to future production", "(1,342)", "6,648", "771"], ["Extensions, discoveries and improved recovery, less related costs", "1,290", "700", "1,349"], ["Development costs incurred during the period", "1,251", "1,030", "609"], ["Changes in estimated future development costs", "(527)", "(552)", "(628)"], ["Revisions of previous quantity estimates", "1,319", "820", "948"], ["Net changes in purchases and sales of minerals in place", "30", "4,557", "33"], ["Accretion of discount", "1,882", "1,124", "757"], ["Net change in income taxes", "(660)", "(6,694)", "(627)"], ["Timing and other", "(14)", "307", "97"], ["Net change for the year", "(2,083)", "4,186", "620"], ["Beginning of year", "10,601", "6,415", "5,795"], ["End of year", "$8,518", "$10,601", "$6,415"], ["Net change for the year from discontinued operations", "$(216)", "$162", "$(152)"]]}

Question: what was the average upward revisions of cash flow of previous quantity estimates during the three year period , in millions?
Evidence:
table_6: ( in millions ) the revisions of previous quantity estimates of 2006 is 1319 ; the revisions of previous quantity estimates of 2005 is 820 ; the revisions of previous quantity estimates of 2004 is 948 ;
Program: table_average(revisions of previous quantity estimates, none)
Answer:
str_answer: 1029
exe_answer: 1029