Oil prices plunged further early Friday on weak economic data and an uptick in U.S. crude oil supplies -- ducking under $84 per barrel. West Texas Intermediate crude oil for July delivery lost $2.77 to $83.76 per barrel on the New York Mercantile Exchange, with the U.S. Labor Department announcing the unemployment rate rose from 8.1 percent to 8.2 percent in May. The Energy Information Administration said U.S. inventories rose by 2.2 million to 384.7 million in the week ending Friday. Weak manufacturing data from China and Europe added pressure to prices. Natural gas for July delivery gave up 7.7 cents to $2.345 per million British thermal units. Home heating oil lost 4.95 cents to $2.6537 per gallon. RBOB gasoline futures for July delivery were off 5.01 cents to $2.6726 per gallon. At the pump, the national average price of unleaded gasoline dropped to $3.611 per gallon from Thursday\'s $3.62, AAA said.