People typically quote from this source
Actual 4,662.25M
Is this an accurate number? Seems like your number is fairly close to this number but your chart looks a bit different, but that could be the scale issue. It is possible to plot a chart of DEC supply last 90 days, which is what the website provide. I like to do an independent validation, if that is possible.
I will provide you the entire file with the data tommorow ... now in bed :)