Each Splinterlands card has a finite print run, and cards are never printed again once the print run ends.
The circulation for each Splinterlands card can be found on the CARDS page.
This number represents the total number of the selected card in circulation. If new copies of a card are currently being found in Booster Packs or Loot Chests, then the circulation increases. Whenever copies of a card are combined or burned from the supply, the circulation goes down.
When cards are combined to level them up, many cards become 1 card. For example, if 20 individual Goblin Shamans are combined, those 20 individuals (1 BCX each) are removed permanently from supply and a single new Goblin Shaman (20 BCX) is created. So the net, in this case, is a loss of 19 Goblin Shamans from circulation.
When Booster Packs are opened, each card flipped has a unique chance of dropping a card from the current set based on universal rarity chances. This means that as long as some Booster Packs from each set have not yet been opened, the exact maximum supply of any specific card from that set cannot be determined, only estimated.
With Reward cards, on the other hand, there is a finite set number of each card that will be issued. Therefore, the print run of each Reward edition card can be tracked on the basis of what percentage has been printed. The print status of each Reward card can always be checked at THIS TOOL, created by community member @kiokizz.
Once a card is no longer printed, the circulation of that card will only go down, because the cards in circulation can only be transferred, combined, and burned.