Numbers of the Week 15% The Chinese central bank raised the bank reserve requirement ratio up another 0.5 percentage points to 15 percent in a bid to cool down the white-hot economy and curb liquidity, which propped up the country's asset prices. 2,630 meters China National Offshore Oil Corp. announced the company had successfully built a 2,630-meter tunnel under the Modaomen watercourse in south China's Guangdong Province, making it the longest horizontal directional drilling operation in the world.