How many copies did Pokémon Gold, Silver and Crystal sell?

Gold and Silver combined sold 23.73 million copies worldwide, the figure Bulbapedia's sales list carries from Nintendo's data as of September 2009. In Japan alone, the pair's first week set the pattern, and Crystal would add 549,135 copies in its own Japanese first week in December 2000.

Crystal sold 6.39 million copies, the smallest share of its generation, as third versions usually do: the committed bought it, the satisfied kept their Gold and Silver, and its audience skewed toward the players who cared about exactly the refinements it offered.

The generation total, roughly 30 million cartridges, puts Generation II second only to the first in the series' history, a remarkable result for games that asked players to return to a world they already knew, expanded in every direction at once.

Scarcity on today's shelf is therefore not about print runs. Thirty million cartridges were made; what is scarce is the complete object, box, inserts and a save battery that has not yet taken the file with it.