Crude oil prices dropped to less than $79 per barrel in New York Thursday on weak manufacturing data from China. West Texas Intermediate crude for August delivery started the day near $80 per barrel, but closed at $78.31. Natural gas for July delivery shed 0.4 cents to hit $2.578 per million British thermal units. Home heating oil added 0.99 cents to $2.533 per gallon. Gasoline moved higher, adding 0.81 cents to reach $2.4601 a gallon. At the pump, the national average price of unleaded gasoline lost a penny, dropping to $3.472 per gallon from Tuesday\'s $3.487, AAA said.