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