April 27, 2017 21:07 Updated Follow Go to the IRS site here for more information. Related articles How can I change the federal income tax withholding election for my retirement benefit? How are federal tax withholding rates for my INPRS retirement benefit calculated? What is the Lump Sum Death Benefit? (1977 Fund) How do I begin participating in the DROP? Where can I find additional information on federal income tax withholding?