H.H. Scullard, in A History of the Roman World 753-146 BC. (London: Methuen & Co. Ltd., 1980) says that based on records of these taxes, by 209 B.C., an estimated 1350 slaves may have been manumitted each year.
In Plautine comedy slaves are shown trying to gather enough money (peculium) to pay for their freedom which would have included the manumission tax.
