(Reuters) - U.S. crude oil hit a record high of $92.22 a barrel on Friday.

Strong demand for crude and a weak U.S. dollar have fuelled the rally from a dip below $50 at the start of the year.

Adjusted for inflation, oil is still below the $101.70 peak hit in April 1980, according to the International Energy Agency, a year after the Iranian revolution.

DOLLAR WEAKNESS

The fall in the value of the dollar against other major currencies has helped drive buying across commodities as investors view dollar assets as relatively cheap.

It has also reduced the purchasing power of OPEC's revenues and increased the purchasing power of some non-dollar consumers.

OPEC oil ministers have noted that although prices are rising to record nominal levels, inflation and the dollar have softened the impact.

The group's OPEC reference price in nominal terms was $74.18 in September, but was valued at $50.98 when adjusted for inflation and the weak dollar.

Some analysts say investors have been using oil as a hedge against the weaker dollar.