Filing Turbo Tax Roth IRA Recharacterization

Hi everyone, while filing tax return over the weekend, I just realized I exceeded the income limits for a Roth IRA in 2019.  So, I re-characterized the entire 2019 Roth IRA contribution amount $5,000 into a Traditional IRA. When I was doing the Turbo Tax Premier reporting, there is a template asking for the "Contributing Date", "Recharacterization Date" and Reasons for recharacterization. I made the contributions every month in 2019. Should I put in the last contribution date (December) or the first contribution date (January)?? Thanks for helping!