Thought this was interesting....found it in Suetonius. Speaking about Augustus' will
"He also left a bequest of 400 000 gold pieces to the
Roman commons in general; 35 000 to the two tribes with which he
had family connections; 10 to every Praetorian guardsman; 5 to every member of the city cohorts; 3 to every
legionary soldier."
Then Suetonius quotes directly from the will:
"My heirs will not receive more than 1 million 5 hundred thousand gold pieces; for, although my friends have bequeathed me some 14 million in the last 20 years nearly the whole of this sum, besides what came to me from my father, and others has been used for the benefit of the State"
It appears then that there was quite a
good number of
gold coins around by the end of Augustus' reign.