Oil prices topped $91 a barrel of crude Tuesday morning with equities higher in Asia and Europe. In Taiwan, the TAIEX index rose 2.89 percent. In China, the Shanghai composite index rose 1.2 percent. In Europe, the CAC 40 in France rose 1.36 percent, while the OMS Stockholm index in Sweden rose 1.53 percent. The price of West Texas Intermediate for July delivery added 75 cents to $91.61 per barrel. Natural gas for June delivery lost 3.7 cents to $2.59 per million British thermal units. Home heating oil added 1.65 cents to $2.8494 per gallon. RBOB gasoline futures for July delivery were up 2.87 cents to $2.8604 per gallon. At the pump, the national average price of unleaded gasoline dropped to $3.636 per gallon from $3.641, AAA said.