How can I calculate zakath on deposited money in Islamic bank?

One year before, I had some money which was deposited in an Islamic bank. Last year I paid zakath (obligatory alms) on the deposited amount of money. Do I have to pay zakath on same deposited money this year too? If so, do I have to calculate zakath on initially deposited amount or Inclusive profit shared with me or only for the profit gained by me from deposit?

Dear Brother / Sister,

You must pay alms via the latest total amount of money. So, you have to give alms the fortieth of both the capital money and its profit.

Questions on Islam