Widespread insurgency and sabotage occurred during the 2003–2008 height of the American occupation of Iraq, coinciding with rapidly increasing oil demand from China and commodity-hungry investors, recurring violence against the Nigerian oil industry, and dwindling spare capacity as a cushion against potential shortages. This combination of forces prompted a sharp rise in oil prices to levels far higher than those previously targeted by OPEC. Price volatility reached an extreme in 2008, as WTI crude oil surged to a record US$147/bbl in July and then plunged back to US$32/bbl in December, during the worst global recession since World War II. OPEC's annual oil export revenue also set a new record in 2008, estimated around US$1 trillion, and reached similar annual rates in 2011–2014 (along with extensive petrodollar recycling activity) before plunging again. By the time of the 2011 Libyan Civil War and Arab Spring, OPEC started issuing explicit statements to counter "excessive speculation" in oil futures markets, blaming financial speculators for increasing volatility beyond market fundamentals.