Prepositions 'in' or 'of' for referring to a population of a country

I was wondering about these prepositions in and of. Actually I was making an assignment in Spanish and I came across this problem and I translated it in English but I am still puzzled as to what the difference is in:
"The population of America..." and
"The population in America..."

when do you use each or is there no difference at all? thank you in advance.

"The population of America . . ." sounds as if it should be followed by "is 300,000,000" or "was 200,000,000 in 1913," or "has increased blank percent in the last 50 years." The preposition of seems to be go best with the population as a whole, not with the various segments within that population.

On the other hand, "The population in America . . ." sounds as if it should be followed by any of the following: 1) "is comprised of 20 percent Black; 53 percent white; 15 percent Hispanic," etc.; 2) "has grown by 128 percent since 1913"; 3) "[comma] compared to the next-most populous nation in the world, is only 20 million fewer people"; or 4) "in the over-85 age-group has grown significantly in the last decade, from 12 percent of the total population to 18 percent of the total population."

The preposition in seems to work best when addressing the various segments (plural) within the population (see number 1 above), or a segment--as in a rate, percent or percentage--that represents an increase or decrease (see numbers 2, 3, and 4 above).

There may be a few exceptions to the above, but the information on the whole is likely accurate.

I think the only time you'd use "in" in such a case is if you were using "population" in its meaning of "a group of people" that you wanted to place geographically, e.g.:

• Among Spanish speakers, the population in America is the most likely to use "America" to refer to the United States of America.

...or if, for some reason, you wanted to (confusingly) use "population" to mean "the action of populating an area" you could also say something like:

• Population in America will exceed emigration for the foreseeable future.

If you are nominating the statistic called "population" (i.e. how many people there are), which you seem to be in your examples, then "of" will serve you better every time, as in:

• The population of America is 309 million.
• The population of America was 97 million in 1913.
• The population of America is 72% white, 12% black, 16% Hispanic, etc.
• The population of America has grown 317% since 1913.
• The population of America, compared with the next-most populous nation in the world, is 78 million more people.