 The alloy was changed to nickel-plated steel, which saved 25% of minting costs and the edge was smoothed.The changes were brought about as the fifty cent had once been the pre-decimal crown which had a higher buying power.The immediate production of the smaller coin was a face value of NZ$35.1 million (70.2 million coins) and entered circulation on 31 July 2006 alongside the larger coin.