[BjoernKW]

Though technically not salary but revenue freelancing or rather self-employed consulting is a realistic option for reaching that kind of annual income.

One piece of advice though: Don't do it for the money (or the money alone, at least). If you want to run a sustainable consulting practice you have to be passionate about what you're doing and constantly deliver high-quality work.

Confidently marketing your services is essential. If you're good at solving important problems for your customers that should be reflected in your rates. Speaking of which, if possible adopt value-based pricing instead of time-based, i.e. daily or hourly, rates.