Which preposition to use with unsuitability

of Occurrences 6%

The unsuitability of the Tyne as a collecting port was remarked upon by the Naval Staff, as well as other objections to the scheme as put forward from Scapa.

for Occurrences 1%

The inspection of workshops where women are employed has, in several instances, fallen back into the hands of Men Inspectors, whose unsuitability for this work first called women in England into the Public Health Service.

Which preposition to use with  unsuitability