"1899", "2546", "2786"], ["changes in estimated future development costs", "-1349 ( 1349 )", "-2153 ( 2153 )", "-3773 ( 3773 )"], ["revisions of previous quantity estimates", "2526", "1117", "5110"], ["net changes in purchases and sales of minerals in place", "233", "-20 ( 20 )", "-159 ( 159 )"], ["accretion of discount", "2040", "1335", "787"], ["net change in income taxes", "-6676 ( 6676 )", "-4231 ( 4231 )", "-4345 ( 4345 )"], ["timing and other", "130", "250", "-149 ( 149 )"], ["net change for the