The interesting part of the question, I think, is in whether or not "an independent minded woman" is a set phrase.
Set, or fixed phrases are relatively immutable patterns of words that have taken on an idiomatic meaning, often bearing an intentional connotation peculiar to the expression.
While quantitative measures such as Ngrams can demonstrate frequency of occurrence, they cannot always point reliably either to intention or acceptance in current contexts.
With this caution in hand, I believe that "independent-minded woman" may have been a set phrase in the mid-20th century, at least in the US. There, and at that time, it may have been a convenient euphemism, an ironic descriptor for a woman whose self-direction may have been at odds with then-accepted ideas of propriety.
I believe that "independent minded" has regained a measure of innocence in the light of new Western views of gender fairness, and that it can be applied with equal objectivity to women, men, persons, and shadings between.
At least that's my independent-minded sense of it.