I think if your just honest and you put down whatever you can remember, you'll be fine. If you put down 2-3 incidents and they find a 4th later on, and it's a simple speeding ticket (and not a DUI) you'll be OK. I honestly can only remember 2-3 fines, but I might have had one or two more, but they've been so many years in the past that I'm not too worried about it.

Incidentally, here in San Diego this morning I watched a CHP officer handing out tickets to bicyclists who were biking through a stop sign. Must have had it in for them. Either than, or it's getting close to end of month quota time.