[["( in millions )", "2004", "2003", "2002"], ["sales and transfers of oil and gas produced net of production transportation and administrative costs", "$ -2715 ( 2715 )", "$ -2487 ( 2487 )", "$ -1983 ( 1983 )"], ["net changes in prices and production transportation and administrative costs related to future production", "950", "1178", "2795"], ["extensions discoveries and improved recovery less related costs", "1352", "618", "1032"], ["development costs incurred during the period", "711", "802", "499"],