Small doubt

Although women's wages are improving, Department of Labour statistics show that the ratio of earnings
with that of men have been roughly static since 1960.

- with that of men have been
- to that of men are
- to those of men have been
- with those of men is
- to those of men has been

Ratio with does not exist correct? It must be ratio to. And as the subject is singular a plural verb tense is incorrect.

Am I missing anything in my reasoning?
Cheers
Lukas