How to report PYEI if I elect to use it for EITC but 2019 was joint return and in 2020 I'm divorced head of household?

So, I want to elect to use prior year earned income from 2019 for figuring my earned income tax credit for 2020 because that income is higher thna 2020 but still makes me eligible for EITC. I would enter my 2019 earned income and write PYEI on line 27 of 1040. But in 2019 I was married and filed taxes jointly. Now, in 2020 I'm  divorced and kids were declared my tax dependents in divorce decree and only I support them and I am filing my 2020 taxes for the first time as head of household. So do I enter my PYEI (prior year earned income) figure as HALF of what my ex-spouse and I jointly earned/reported/filed in 2019? or do I enter only what I individually earned (on my W2) that was part of the joint 2019 total?