<prompt> Translate the following text to EnglishHata 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.  <response>: However, the annual growth rate of bill mail is declining, whereas the annual growth rate of advertising mail is increasing fast. 