Worldwide rig utilization decreased the week ending December 15, according to Offshore Data Services (ODS). With 560 of the world's 647 mobile offshore drilling rigs under contract, worldwide offshore rig utilization fell 0.6 percent to 86.6 percent. The rig utilization rate in the U.S. Gulf of Mexico fell because of a one-rig decrease, bringing the number of mobile offshore drilling rigs in the Gulf under contract to 181 out of 207, bringing utilization down 0.9 percent to 87.4 percent. The European offshore rig count fell by one, with 87 of the 101 mobile offshore drilling rigs in the region under contract, pressuring utilization to down one percent to 86.1 percent, ODS said. ODS' total worldwide offshore rig count includes changes in utilization and fleet size in regions beyond just the Gulf of Mexico and Europe.