I never had that specific toy but based on my experience with other toys from that time frame, I’m guessing the success rate was around 50%.
From what I’ve gathered the pegs were a bit large and the figures often ended up oddly hanging off the side rather than fall of.
However, I was mostly fascinated by the Kenner employee who apparently felt that Luke “should” be fed to the Sarlacc.
Well yes, he “should” be, but I’m guessing the attempt failed roughly half the time.
I’m not sure if I was clear about that in my previous post, based on your subsequent post.