Did you have a distribution this year that you maybe haven't had in the past?
The information is needed to calculate the Line 22, page 18 (see link below) - its related to nonqualified withdrawals.
https://www.tax.ny.gov/pdf/current_forms/it/it201i.pdf
It seems to be a bug in TurboTax 2018. I didn't make any non-qualified withdraws, but the software asked for this anyways. The good news is that TurboTax did not mistakenly use this to affect my bottom line.