The AMS (American Mathematical Society) has done an employment survey for years --- see http://www.ams.org/profession/data/annual-survey/annual-survey http://ww

The AMS (American Mathematical Society) has done an employment survey for years --- see http://www.ams.org/profession/data/annual-survey/annual-survey http://www.ams.org/profession/data/annual-survey/annual-surv... I'd hope other professional organizations do the same thing, so there should be no need to guess or extrapolate to get pretty good numbers.