Business & farm

I just received a 480.6C for the first time. It is for 2020 dividends on a regular taxable account. I understand the reporting on a 1099, but for conversion to USD - what date of conversion do I use? Last day of year (12/31/2020) or actual dates interest paid (in this case 6/12/2020, 9/11/2020 and 12/11/2020)? Thanks!