Liechtenstein coins are so rare that they do not actually circulate, and no banknotes have been issued, with the exception of 3 emergency issues of "Heller" in 1920. Most of the Liechtenstein frank coins have the same amount of precious metal as the Swiss franc, except for the coins minted in the late 1980s and 1990s. The highest number of coins minted was the 1 frank minted in 1924; 60,000 were struck, but 45,355 were melted. If the number of melted coins is excluded, the highest mintage would be the 50 Franken minted in 1988 commemorating the 50th anniversary of the reign of Prince Franz Joseph II and the 10 Franken minted in 1990 commemorating the succession of Prince Hans-Adam II, both having a mintage of 35,000 pieces each.