Which preposition to use with manpower

for Occurrences 3%

The purpose of this was to secure manpower for the army and also slaves for sale; for the south-west had for centuries been a main source for traffic in slaves.

in Occurrences 3%

The raw material of manpower in America is magnificent in numbers and quality, but it has to be equipped and trained and brought across the Atlantic.

of Occurrences 1%

Red Perris also was in the last stage of exhaustionone true pitch would have hurled him limp from his seatyet, with his body numb from head to toe, he managed to keep his place by using that last and greatest strength of feeble manpower of will.

to Occurrences 1%

The result is an aggregate of parts, differing in many local respects, but acknowledging the authority of the power center and contributing material goods and manpower to its support and defense.

Which preposition to use with  manpower