I would think programers, engineers, doctors and others in technical escapades, would be limited, per capita, compared to others, mostly because of the way they have to think, in order to preform their function. Creativity is usually spurred, often by those that just seem to "have it", which is also usually quite apparent. The technical side of the work at "DreamWorks" (for example) would have far different people, then the conger side of the coin. Simply put, creativity is a unique skill, though you can train to be more creative, most folks just are average. This would be true of any industry I suspect, though writers, graphic and other artists, musicians, etc. would seem to have a better grasp, in regard to creativity. Finding creativity in a fairly rigid industry such as ours, just rubs the wrong chords in the brain.
Having the technical prowess to work CAD, is in direct conflict with most people's creative juices, likely similar to the technicians that take the story boards at DreamWorks and turn them into feature films. Another example is, a much higher percentage of artists are left handed, compared to the rest of the population, the same is true of actors. Perfectly reasonable. I'm left handed, but having gone to parochial school, the nuns forced me to be right handed. I didn't find out until high school, when I had an eye test. The left/right brain test, mentioned previously in this thread, showed I was 49 left, 51 right, so maybe I use enough of both to gain and edge in creativity. I've always been creative, sometimes wildly so, though I know many that are much brighter than I, they do seem to lack this level of "exploration" or "visitation" to the unkown, different or just plain weird. I honestly think it's just a mind set and some have it, some have gotten better at it with effort/training, but many just don't explore the possibilities or the vulgarities of their "depths". Lastly, I've noticed the most creative people I've met, are also full of a quite demented sense of humor. Truly sick and disturbed, but damn funny and creative. I'll bet this is a similar portion of the brain causing both.
FWIW . . .