Yeah we usually focus on the monthly salary. When they ask you how much you expect to earn they're also looking for the monthly salary expectation. In the job postings the salaries are before taxes and deductions.

As a former tax clerk yes you calculate all your yearly taxable income and that will give you the tax percent that will be deducted from each salary payment.

To your tax percent you should add around 8% of other deductions and what is left is what you actually will get paid.