What percentage of pentests in real world result in succesful exploitation/initial access?

Hi, as an aspiring red teamer with a fair bit of time spent on HackTheBox and TryHackMe but little in real world pentesting, im wondering how common it is to find an exploitable vulnerability in an actual live system with firewalls, XDRs, etc in place?

My guess is since the real world systems aren't deliberately made vulnerable as CTF systems are, there would be many cases where a pentest would not result in successful exploitation. But how often does that …

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