<prompt> Translate the following text to SwahiliIn use since Roman times, today the salt pans are the source of 18,000 metric tons 20,000 tons of salt a year.  <response>: Kwa kuwa maji hayo yanatumiwa tangu nyakati za Waroma, leo matope hayo hutokeza chumvi ya tani 18,000 kwa mwaka. 