In recent years, the imbalance between economic demand and the supply of key industrial inputs such as water has been especially stark in traditional agricultural powerhouses such as Henan, Shandong and Hebei. There, the exponential growth in water consumption for both consumer and industrial purposes (most notably, by the coal and steel industries) has far outstripped native water reservoirs' capacity. Despite housing roughly one-quarter of China's population and accounting for a similar portion of gross domestic product, the provinces of the North China Plain, including Beijing municipality, hold only 8 percent of China's total water resources. The eastern stretches of these provinces' primary traditional source of water for agricultural use, the Yellow River, now runs dry up to 230 days a year.