I do indeed expect it to be a rare event, and 5-10% implies one flight in every 10 or 20. In that context my 70 long haul sectors without an OpUp strikes me as really rather bad luck.

I can't use miles to upgrade by the way, since I fly a major-company-route travel-agent tickets (still not particularly cheap), rather than direct ba.com tickets, that can't be upgraded with miles, but of course I do use miles + GFU2s for holidays in First.

Am sanguine about it and so long as I get my 62A/K or 64A/K it's really no big deal, but just don't take my advice at the roulette table...