I don’t know why you’d want to know, but in NSW adjustments to the monetary value of a penalty unit is made by the Treasurer, via The Office of State Revenue, and under the provisions of a fancy bit of Legislation called the Statute Law (Miscellaneous Provisions) Act 1997; so a search on their website or in fact on any “regulators” website such as Police, Fair Trading, WorkCover, or EPA would be a good start.