I have to say that such a figure is seriously misleading.
Why? Because some clubs I know get their students in the circuit by 5-7 hours...problem is that almost ALL students are still stuggling to fly the a/c at such low hours and are woefully unprepared for circuits. This comes from my experience at a club that most students stuggled to fly upwind-crosswind climb followed by level off & turn downwind+RT...needless to say I dont think much of such a training regime and dont teach there anymore.
On the other hand, at my club students dont reach the circuit until about 11 hours of training have been completed - thoroughly covering ex1-11 & the student *can* fly the aircraft to a good standard. The student is likely to solo at around 15 hours - the average to solo varies only a little around these figures due to the nice standardised nature of the training course prior to solo, but this figure can vary depending on breaks in their flying...more current = less extra revision.
One student I had (with no previous flying experience who was trained under the standardised regime) did his 11 hours pre circuit training entered the circuit and flew a great circuit first time out doing all the RT. Fantastic....only really needed to teach him the landing....and thats how it should be...
So bottom line...average to time to solo is greatly affected by basic experience levels and standardisation of training. With no prev exp. < 10 - they probably weren't properly prepared, ~13-17 - average IMO, >25 the student has either had breaks in their training, or they are in the category of student that finds the circuit difficult & should discuss it with their instructor, or worse case - they should consider another hobby/career.
50hrs to solo (as in one case I know of...no medical restrictions/issues) frightens the pants off me...they guy *really* should not be flying solo...ever...I personally would fear for any passengers he would carry - and I certainly hope that he will not get passed the examiners.....if he does then my faith in examiners may be lost overnight...
125 hrs?!