Comparing the gross salaries of employees between countries is meaningless. You are e.g. comparing after employer taxes, which have large differences between countries.
To meaningfully compare countries you need to either compare the gross wage costs per employee that a company actually faces or compare the net income of employees after all taxes. And correct for purchasing power of course.
Which has exactly the same sort of problem. If a government reduces employer taxes and increases employee taxes, you have a magical free gross wage growth.
You can't make incomparable values comparable by reducing them to a ratio, except in special cases.
To meaningfully compare countries you need to either compare the gross wage costs per employee that a company actually faces or compare the net income of employees after all taxes. And correct for purchasing power of course.