TULSA, Okla. ( TheStreet) -- Helmerich & Payne ( HP) reported expectedly weak earnings on a day when the entire oil services sector slipped. Weak drilling activity across the U.S. was the primary culprit for a 59% drop in income: operating income for U.S. land operations was $90 million in the fourth quarter, compared with $158 million in Q4 2008. Operating revenue fell 38% to $362.2 million. It might not be any consolation to the company or its investors, but Helmerich & Payne was far from the worst performer in the oil services segment of the energy market on a day when the entire energy sector dropped close to 2% by mid-afternoon. The stock was down 1.83% to $37.48. In fact, just four of the 86 companies in the oil services sector were in positive territory during the day's trading session: North American Energy Partners ( NOA) (+2.81%); Energy Services of America ( ESA) (+1.64%); NuStar GP Holdings ( NSH)(+0.33%); and Inergy Holdings ( NRGP)(+0.30%). Two stocks that looked liked winners but ending the day slightly to the downside were Boots & Coots ( WEL)(-0.75%) and Allis-Chalmers Energy ( ALY)(-0.28%).