Global oil demand growth in 2012 remained unchanged at 0.9 million barrels a day, but uncertainty surrounds the 2013 forecast, OPEC ministers said Thursday. For now, however, the Organization of Petroleum Exporting Countries, based in Vienna, was not changing its 2013 forecast of 0.8 million barrels per day, MarketWatch.com reported. \"World oil demand has overcome earlier expectations of a declining momentum and moved to a more stabilized trend, supported by the summer driving season, the summer heat, and the continued shutdown of most of Japan\'s nuclear capacity,\" the ministers said in their monthly oil market report. OPEC also said there was \"considerable uncertainty surrounding the forecast for world oil demand growth in 2013.\" Non-OPEC oil supply was expected to increase by 0.7 million barrels per day in 2012, MarketWatch.com said. In 2013, the supply forecast is 0.9 million barrels per day.