In Norway we are obliged to deduct taxes on the payroll, for advance payment to the goverment. This can be done in two ways, some people have a fixed rate (like 33%) and some have a table key that one must use as a lookup with the gross amount to get the deduction. For example if you have a gross pay of NOK 30000 and have been given table 7100 then you should be deducted NOK 9 253.

How can this be impemented in OpenERP payroll? Is this what contribution registers are about, because I have not really found any good clues to what they are used for.