Maybe this will helpGas Measures for Production...

Maybe this will help

Gas Measures for Production reporting

Symbol
Gas Measure Measure
(volume) Scientific Notation Ft3 BTU’s
Approximate
Ft3 Cubic Foot 1 1,000
Ccf 1 hundred cubic feet 1X102 100 100,000
Mcf 1 thousand cubic feet 1X103 1,000 1,000,000
(1 Decatherm)
Mmcf 1 Million cubic Feet 1X106 1,000,000 1,000,000,000
(1,000 Decatherm)
Bcf 1 billion cubic feet 1X109 1,000,000,000 1,000, 000,000,000
(1Million Decatherm)
Tcf 1 Trillion Cubic Feet 1x1012 1,000,000,000,000 1,000,000,000,000,000
(1 Billion Decatherm)
A home using an average of 69 Ccf per month would use 6900 Ft3 /month which would be 6900 X 12 = 82800 Ft3 per year, or about 83 Mcf in a year.