<prompt> Translate the following text to SwahiliHowever, the annual growth rate of bill mail is declining, whereas the annual growth rate of advertising mail is increasing fast.  <response>: Hata hivyo, kiwango cha ukuaji wa kila mwaka wa barua ya muswada ni kupungua, wakati kiwango cha ukuaji wa kila mwaka wa barua ya matangazo ni kuongezeka kwa kasi. 