How much methane does a landfill produce?

I have been doing a lot of research to try to determine how much methane or LFG an actual landfill can produce.  Many factors go into the production of the LFG and include, age of garbage, temperature, moisture level, and type of garbage.  In general the more organic the garbage the more methane and carbon dioxide that is produced.  Also, the warmer the better and the higher the moisture content the better. As for the age of the garbage there are wide ranges of time periods where many experts say the LFG production is at its peak.  Gas production normally starts around the 1 to 3 tears after the garbage has been covered, and after 5-10 years gas production is at its peak.  There are many different suggestions to when the landfill stops producing gas ranging from 10 - 40 years.  And many times the life of gas production varies depending on the conditions of the landfill and its contents.  Here is a quick video that show LFG being emitted from a bore hole drilled into a garbage layer.  Sure does seem like a lot of LFG being produced!