The answer to this very broad question depends on many factors such as (but not limited to):

• field: I can't really say if the same position in one field makes more than another but it's very possible.
• country: see other answers; North America or Western Europe are waaay to broad to be clumped into a single bucket. (see below for approx figures from Sweden)
• university/city: bigger and more expensive cities usually call for larger figures, but in practice you don't get richer on that due to higher cost of living (particularly rent)
• financing: postdoc but where? ... at a company/university/independent research institute? In certain systems it's also possible to apply for postdoc grants (in Swedish), I know some people who have gotten grants that include their own salaries. Getting such a grant means your financial burden on the employer is much less.
• tax: some countries have special, time-bound tax classes for "visiting scientists" or something like that, I have heard that Denmark has a such a policy

That being said, I have got a figure of approx 32500 SEK/mon (in Swedish) which corresponds to roughly €45000 per annum (The source is a labor union for university employees).

Hope that helps

The answer to this very broad question depends on many factors such as (but not limited to):

• field: I can't really say if the same position in one field makes more than another but it's very possible.
• country: see other answers; North America or Western Europe are waaay to broad to be clumped into a single bucket. (see below for approx figures from Sweden)
• university/city: bigger and more expensive cities usually call for larger figures, but in practice you don't get richer on that due to higher cost of living (particularly rent)
• financing: postdoc but where? ... at a company/university/independent research institute? In certain systems it's also possible to apply for postdoc grants (ref in Swedish), I know some people who have gotten grants that include their own salaries. Getting such a grant means your financial burden on the employer is much less.
• tax: some countries have special, time-bound tax classes for "visiting scientists" or something like that, I have heard that Denmark has a such a policy

That being said, I have got a figure of approx 32500 SEK/mon (ref in Swedish) which corresponds to roughly €45000 per annum (The source is a labor union for university employees).

Hope that helps