It's not "very small", it's just significantly below unity. In, say, physics, I'd say that somewhere around 50% of PhDs wind up, long term, in professional rese

It's not "very small", it's just significantly below unity. In, say, physics, I'd say that somewhere around 50% of PhDs wind up, long term, in professional research positions. That's 30% in academia, and the remaining 20% in government/military/commercial research labs.