I'm using the Current Results object to track scores. It returns a score of the number of correct answers. I want it to be a percentage. How can I do this?

The variable returns a normalised raw score, that's what its designed to do and its what any LMS expects. It would be rather hopeful to expect there to be a special method for stand alones and LMS hosted materials, you'd loose a lot of flexibility.
But you can define another variable and have it present the results in any way you want it to.
Module / runtime settings / etc