Gas prices are still heading downward.

The price at the pump has dropped about 35 cents over the past two weeks.

The national average is now around $3.31 per gallon, according to a report by the Lundeberg Survey.

Wichita, Kansas has the cheapest gas at $2.79.

The lower prices are a result of the tumbling price of crude oil. Last week it dropped below $78 a barrel.

Now Goldman Sachs is predicting crude prices could drop as low as $50 a barrel.