NEW YORK -- Oil prices tumbled more than $6 a barrel Friday - the biggest one-day percentage plunge in nearly four years - after a rebounding dollar and a Russian troop pullback in Georgia sparked another frenzied sell-off, according to The Associated Press.

Crude's nosedive wiped out all the gains from the previous day's big rally and reaffirmed the belief that high energy prices are still cutting into consumer demand for fossil fuels in the U.S. and overseas.

Light, sweet crude for October delivery fell $6.59, or 5.43 percent, to settle at $114.59 a barrel on the New York Mercantile Exchange.