《明史·志·卷五十五》
正统初年，运粮的数目是四百五十万石，而兑运二百八十万余石，淮、徐、临、德四个粮仓支运占十分之二四而已。
正统初，运粮之数四百五十万石，而兑运者二百八十万馀石，淮、徐、临、德四仓支运者十之三四耳。
In the early Zhengtong period, the number of grain transported was 4.5 million units, while the number of grain transported in exchange was over 2.8 million units, and the number of grain transported from Huai, Xu, Lin and De accounted for only 24%.