However, the coining of the new Yuan Shih Kai silver dollar was closely connected to the withdrawal and re-minting of the existing 280 million dragon dollars, the fineness of which was considerably below the new standard. In order to facilitate the introduction of the new coin the China Government arranged that the Bank of China, the Bank of Communications and the official provincial banks should exchange, free of charge, the old dragon dollars against the new Yuan Shih Kai silver dollars. During the period from 1914 to July 1917, about 30 million Mexican dollars were exported from China, and in addition 19 millions were melted by the Mints for re-coinage. Both these measures continued in an extended form during the following five years, thus making room for the new Yuan Shih Kai silver dollar which, by 1919, had succeeded in firmly establishing itself. The dies were distributed by the Tientsin(Central) Mint to the various provinces. In the course of time the dies were worn and had to be either retouched or re-engraved. In this way it happened that many varieties of the Yuan Shih Kai silver dollars were found. It can be stated that, until the end of 1917, altogether there were 184,946,487 pieces of Yuan Shih Kai silver dollars have been struck by the Mints in China.