A common statistic I see quoted about COBOL is that there are "more than 200 billion lines of COBOL in existence with an extimated 5 billion of new code [written] annually". This statistic comes from a 1997 study by the Gartner Group. Archive Link Here

A more recent study by Vanson Bourne (commissioned by Micro Focus) in Feburary 2022 estimated that there are actually around 775-850 billion lines of COBOL in daily use. Archive Link Here