0-time Tube Challenger here with an FNC attempt pencilled in for Friday 28th April

Got a route, timings etc all planned out and I'm currently at a stage where I'm feeling relatively confident about how the day *should* go down.
This is a hard question but I was hoping for a rough percentage on how many of your attempts have reached completion? I'm not at all concerned with the time for my first attempt but I feel like I'd be really quite gutted if we didn't complete, but also I know it's a serious possibility.
Was just hoping for a bit more clarity on where my expectations of completion likelihood should be. I know it's impossible to exactly remember how many completions Vs non you've had, and it's all context dependent etc but any information you can give is appreciated

P.S Knocking out Olympia early so don't factor that in for ending the run
Cheers everyone