Your basis in the account is the amount you put in. Your earnings came from your investment. Only you know your basis in the ROTH. The broker might but it has probably changed hands so they don't know either. Ask you broker if you no longer have your paperwork.
I want to urge you to create a financial notebook that is kept separate from your tax return. Keep it safe and each year, add your year-end statements from all your financial accounts plus a copy of your W2’s, your carryover information, and proof of your basis in your various investments. You must keep tax records from the time you purchase until sold/ loss used plus 3 years. It is very easy to lose track of disallowed losses, carryforwards, and basis.
This can be a digital or paper notebook.
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