Key FindingsSince 1990, state lawmakers have cut top personal income tax rates 210 times and top corporate tax rates 168 times. Over the same time, lawmakers have increased top personal income tax rates 73 times and top corporate tax rates 42 times. ITEP’s new Historical State Tax Rate Database offers a long-term view of how state tax systems have evolved. Additionally, several states have taken on reforms that don’t affect corporate tax rates but bolstered the tax by broadening the corporate tax base. Many states have repeatedly cut top personal and corporate income tax rates in recent years, sometimes while approving increased sales tax rates as well.