As a former employee who quit your job by retiring, you will need to emphasize that you were unsuccessful in finding alternatives to quitting.

If you were confronted by certain people or manager, speak to these situations during your interviews with the unemployment personnel.  List all of the alternatives that you considered before retiring and then tell why the alternatives did not work.  Explain that you felt the only thing you could do is to retire from the company voluntarily because you felt you may be terminated or forced to retire if you didn’t accept this option.