Oil and gas stocks have gone through tough times lately, and Helmerich & Payne (NYSE: HP) hasn’t been immune from the volatility in the energy industry over the past couple of years. Yet the oil drilling rig builder and leasing company has something going for it that most of its peers don’t: membership in the elite Dividend Aristocrats group, all of which have boosted their annual payouts each and every year for at least a quarter-century.