Roth Excess Contribution – How to determine the first tax year to submit Form-5329 for

I made an excess Roth contribution on 4/10/2017 for the prior tax year (2016). I am planning to fix that now in 2022 by submitting a Form-5329 for each year that the excess contribution remained in my Roth account.

 

My question is this: What is the first tax year that I must submit a Form-5329 for?

   - Would it be 2016 because that was the tax year the contribution was for?

   - Or would it be 2017 because that was the year the contribution was actually made to my Roth account?

 

Thank you!!

Steve