VIENNA (October 14, 2009)--Oil prices jumped above $75 a barrel Wednesday for the first time in a year on investor optimism that demand for crude will improve ahead of the Christmas shopping season.

A weak dollar also bolstered crude prices.

Oil has traded between $65 and $75 since May as traders have considered mixed crude supply and demand data.

Some analysts expect an increase in diesel fuel demand from U.S. truckers supplying inventory for the year-end holiday shopping season will trigger a sustained rise above $75.

Others are more cautious, pointing to high inventory levels, but burgeoning oil supplies this year have weighed on oil prices.