Each state EPA requires operators of plants to obtain permits. The permits will have data on maximum rates of CO2 recovered from the natural gas streams. You may go to stse deparments of environmental quaity and get public records on such data.
Look up in your favorite search engine, EOR, CO2 pipelines and you'll get a lot of information about a system of lines that more CO2 to oil fields. The CO2 is injected into old oil zones to extract more oil. This is mostly in west Texas.
No one would purposely burn methane to make CO2 today. In the 70's that may have happened (I saw one in Wyoming once). There are deposites of 99.9% pure CO2 in Utah and Colorado, so its cheaper to just drill and produce that CO2 than make it from fuel sources.
One of the largest places where CO2 is removed from a natural gas stream so the natural gas will burn is in Wyoming.