The 1-cent coin was changed in 1975 to a twelve-sided shape and aluminium composition. Decagonal 50-cent coins were introduced in 1976 to replace the 50 cent banknote, but production for circulation ceased in 1989, along with that of the 20 cents. In 1990, nickel-brass 1 dollar coins were introduced to replace the banknote of the same denomination. Nickel-plated steel replaced copper-nickel in the 5, 10, and 25 cent coins in 1991 with a smaller size and seven-sided shape for the 25 cent coin. In 1994, a round nickel-plated steel 5 dollar coin replaced its corresponding banknote, a smaller, seven-sided nickel-plated steel 1 dollar coin was introduced, and the 5 cent coin was abandoned. 1995 saw smaller, round copper-plated steel 10 and 25 cent coins. All non-current coins were demonetized in January 1997. A scalloped nickel-plated steel 10 dollar coin replaced the 10 dollar note in 1999 and a bimetallic 20 dollar coin with a nickel-brass ring and copper-nickel center was introduced in place of a 20 dollar banknote in 2000. All nickel-plated or copper-plated steel coins are magnetic.