Got a strange question here.

Today I was at the bodyshop and we were moving the car with the engine off, and had to turn the steering wheel several times. When we put the car up on the lift, I noticed a puddle underneath the engine bay. Determined it to be power steering fluid.

Lowered the car and saw that it had blown out from under the reservoir cap. How is this possible

Also ever since I've owned the car, I believe the pump has been leaking in this fashion. The pump always appears "Wet" when examined. To complicate this issue though, I have never topped off the steering fluid in the time I've own the car. The level appears to be spot on and it never goes down over time. I check it every month or so.