There was an earlier thread on here - could be 3 or 4 years ago now, in which somebody pulled out a newspaper article from 1960 which said that of all the bronze farthings minted from 1860 to 1956 only about a third were returned to the mint for melting down. So if this situation were to apply at all times across all denominations (which I guess is unlikely), there would still be a million 1829 farthings kicking around out there. The opinion was expressed that the number of coins simply mislaid or lost was dramatically underestimated by pretty much everybody. With so many coins doing the rounds, I would, in the nicest possible way, suggest that a database is not really a practical proposition and we will always be reliant upon price guides etc. for estimates of rarity. One further point is that the official mintages simply record the number of coins minted or issued in any one year, many of which will carry the date of the previous or the succeeding year (e.g. 2.5 million pennies were minted in 1869 but it is reckoned that only 400,000 actually carried that date), so unfortunately any figure produced by the Royal Mint must be taken with a massive pinch of salt.