How to handle state tax refunds from prior tax years

I filed my 2017, 2018, and 2019 taxes all in 2020; and I got refunds for all three years from my state.  Since I did itemize, the refund is taxable, right?   TT wants me to input my "total of all your payments and withholding" for each separate 1099-G I received from the state for each tax year.  What does this mean when there are refunds for multiple tax years received in one later tax year?  Do they just want my withholding from my W-2 that corresponds to the tax year for the refund, or am I supposed to add up all of my withholding from all of those years?  What is the idea behind the question?  If I knew the rationale, I may start to understand the question.  Thanks!