Analysts say oil demand growth in China has eased slightly, putting less strain on the global supply system and allowing stocks to build at a time when Opec, headed by Purnomo Yusgiantoro, has been pumping out oil at its highest level for 25 years. Recent data show US stocks are rising, easing concerns about the availability of winter fuels, while markets have also taken heart from indications from Opec that cartel chiefs will stick to current official output limits when they meet in Cairo this week.