It's just an estimated graph I made from the coins in my small pool of a collection, so don't be too hard on me sources:https://www.armstrongeconomics.com/...monetary-history-of-imperial-rome/27bc-217ad/ http://money.visualcapitalist.com/deaths-roman-emperors-vs-silver-coin-content/ https://en.wikipedia.org/wiki/Debasement
Don't be too hard on you? Hardly, as your visual rendition of the debasement of Roman silver, very graphic (in the literal sense) will stick better in people's minds far better than just a bar graph or two. Very nicely done. If i may recommend for your own pleasure in your pursuit of this study, the Kevin Butcher book on the silver coinage of Rome from Nero to the Third century. I think yours is pretty much in accordance with his conclusions but I like you visual representation better. I am not sure but you might want to look into having this chart reproduced for future books covering this aspect of ancients coinage. Again, very nicely done.