1) Out of the 7 billion+ people alive today, around how many have earned a PhD in physics?
2) Around how many physicists are working today?
3) Around how many physicists are being added to the work force yearly?
closed as too broad by John Rennie, Ben Crowell, Michael Brown, Emilio Pisanty, Chris White Aug 30 '13 at 16:31
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I can only offer you some figures I know: in the Netherlands every year around a thousand students start studying physics at the university. In a very crude estimation we can multiply this by 10 (5 years to earn a masters and 4 to earn a PhD) and say that if this number of enrolling students has been constant for quite some time, about 10.000 STUDYING (edit) physicists live in the Netherlands, which is about 0.06% of the Dutch population.
-I recently read that the Netherlands is one of the European countries with the lowest percentage of science students, so the total percentage of the whole of Europe might be higher.
-As mentioned in the comments I forgot the fact that the physicists continue living after studying. Assuming that a person finishes his PhD at his 30th and lives until his 70th (again, everything is very crude here!), and taking into account the fact the fewer people went studying several decades ago, I would say the upper bound is 0.3% physicists.