What do you mean? As far as I know the major tax reform by the right-wing parties was the "work tax deduction" which makes taxes less flat. (The deduction is capped at roughly median income). Top marginal rates have been largely the same since the mid '90s.

Since mid '90s is "rather recent" for me in this domain. I'm talking about the significantly reduced tax burden for the wealthy and corporations due to various tax cuts and abolishments.