In addition to federal depletion allowance of 15%, states that levy income taxes have varying amounts of depletion allowance. Oklahoma, for example, has a depletion allowance of 22%.
Percentage depletion is a gift that “keeps on giving”. In other words, this continues year after year without limit. For most properties, this is the accounting technique used. (If you had a high cost basis in a property, and only had minimal production, you might consider cost depletion.)