File:Fineness of early Roman Imperial silver coins.png

English: Data from Walker, D.R. (1976-78), The Metrology of the Roman Silver Coinage. Parts I to III.

Before the civil war of 69, the exact time of a coin's manufacture within a reign is usually unknown. During and after the civil war of 69, most coins can be identified to the year or two.

These are the data for the denarius and the antoninianus, and hence exclude the quinarius and eastern provincial coinage (drachma, cistophorus, etc.).

Note that according to Butcher and Ponting (2009, "The Silver Coinage of Roman Syria Under the Julio-Claudian Emperors"), Walker's data, which relied on scratching the surface of a coin (rather than completely crushing and destroying the coin), can overestimate the silver content. They argue that the surfaces of the coins that Walker had examined had likely been depleted of copper during manufacture, during the centuries of burial, and during cleaning after their discovery.