CBS hits it right on the head. A lot of students have never stepped foot on a trail before, yet alone climbed anything. They take the mountaineers course as a deep plunge, headfirst, into the world of climbing. Those groups of 12 you see on the Coleman-Deming, Eldorado, Sulphide Glacier, etc. are probably on their first or second climb *ever*. And a good number of them take the class and never climb again - it was a novelty to try out, or they just figured it took too much time, or was not for them in the first place. Others move on and climb on their own. And a few others become instructors and leaders. And of the instructors and leaders, many are 2nd-4th year climbers, who will move on themselves. Only a few stick with the organization beyond that. I'd say the ratios are something like 9:2:1 (worst case) down to 6:2:1 (more typical).