Undo is "done" or "undone"?

After you click "undo" the action is either completed immediately or you see the percentage that shows the progress.

I'm interested in the second case.

As it might take some time to complete this action. That is why in our interface there would be a percentage showing the progress of this action. Which word to better use after this percentage?

Example:

23% done

23% undone

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Done or undone?