Without having seen the contract, I can't say how they've detailed the breakdown of the salary (or thedeductions). However, most likely the 19% is in fact the "employee's contribution" and not the "employer's contribution".

Your chances of negotiating any post-doc salary (unless you are a very highly sought after individual with your choice of pick of several top flight universities) are non existant. University of Berne is public entity and it has a fixed pay schedule (fixed deductions, etc.). Depending on what pay grade you post doc position falls into you will get the amount x.

However, by all means ask for clarification if something is unclear. I would not find it rude after all it is a different country and a different system, and you will need to know how much disposable income you will have in the end and what ancilliary costs you will be facing (average rent, health insurance, length of military service to be done...)

I'm kidding about the last one :-)

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