An oil rig is shown in this file photo.

The price of oil is headed for its biggest monthly decline since December 2008.

Benchmark US crude has dropped nearly 16 percent so far in May on growing expectations that world won't use as much as previously thought this year. The futures contract fell $2.93, or 3.2 percent, to $88.08 in Wednesday morning trading in New York.

Analysts point to weak US jobs numbers and a slowdown in China's manufacturing sector. The US and China are the biggest oil consumers in the world.

Experts also are concerned by a banking crisis in Europe that may pull the eurozone into recession. Economic confidence has plummeted this month in Europe, pushing the euro to its lowest level in two and a half years.

Brent crude fell by $2.69 to $103.99 per barrel in London. - Sapa-AP