9. During the early years of the Nanking Government, Kuomintang regime probably derived one-half to three-fourths of its revenue directly from Shanghai, although exact figures are difficult to determine. Nanking's major sources of income were three: customs revenue (which usually averaged 40 to 50 per cent of total income), income derived from borrowing (which averaged approximately 25 per cent of total income during Nanking's first five fiscal years), and revenue from the salt tax, consolidated taxes and other miscellaneous taxes. Shanghai was the prime source for all three of these types of revenue. Forty to 50 per cent of China's foreign trade was conducted through Shanghai, which thus accounted for a similar percentage of the customs revenue. Shanghai was virtually the only source of income derived from borrowing. During the first five years of the Kuomintang Government, Nanking issued over Y 1,000 million in bonds. With minor exceptions all of these bonds were either purchased by the Shanghai banks or sold on the Shanghai stock exchanges. Even in terms of income from the salt, consolidated and various miscellaneous taxes, Shanghai was the most important source. During the 1927–28 period Nanking's Ministry of Finance could control the income from these taxes only in Chekiang, Kiangsu and parts of Anhwei. Shanghai, which was the economic centre of this region, thus supplied major portions of such taxes as the cigarette surtax. See Coble, Parks M. Jr, “The Shanghai capitalist class and the Nationalist Government, 1927–1937,” Ph.D. dissertation, University of Illinois, 1975, Chap. IVGoogle Scholar.