That would be meaningless if having a citizen was an asset of more or less standard economic worth regardless of country.
But countries can have 10x or 100x as many citizens as others without having the 10x or 100x the same GDP -- in fact they could do much much worse than the other country.
Compare e.g. Nigeria with Japan or Ireland.
The direct comparison between Nigeria and Japan or Ireland is relevant simply because of how incompetent past Nigerian governments have been.
PPP is metric, good for comparing certain things. I wouldn’t think that, for the purposes of determining which is the greater power, less population would be more beneficial as long as the total economic output is greater.
Would they? An incompetent farmer could very easily produce nothing even with 10x the land too.
I don't want to sound like I am dumping on China. The US/etc housing boom was a boost to GDP largely due to low interest rates, but because the assets where poorly allocated the long term value creation was well below what the economic activity suggested. Building something is a critical first step, building something useful that's worth the maintenance and replacement costs is vastly more difficult.
In nominal terms they are 72 per person adjust for PPP and they are #79 which which not bad. It’s the next 30 years when things get interesting. http://statisticstimes.com/economy/countries-by-projected-gd...