How many documented cases are there of patients living over 20 years with Parkinson's?

I'd curious about this....Michael J Fox has had it for what seems like more than 20 years,

My dad was not dxed until he'd had it for about 8-10 years---but that's a guessitmate.

All I know is it's one horrible disease and it scares the bejeebers out of me.

I know a classmate who has had it for 25 years. He was fairly young when he was diagnoised.

How many of us, upon receiving that kind of diagnosis would simply "opt out" of putting their families through the care required?

2 of my kids are Drs. Both has "offered" to help me if that is my choice. This actually is extremely calming to me. 15 years of care for my sweet dad--NOBODY should have to go through that.