<prompt> Translate the following text to SwahiliThe volume of letters sent by households or household originated mail can be obtained from Table 1 by adding the volumes of HH-to-HH and HH-to-NHH mail.  <response>: Kiasi cha barua zilizotumwa na kaya au barua zilizotumwa na kaya inaweza kupatikana kutoka kwa Jedwali 1 kwa kuongeza kiasi cha barua za HH-HH na HH-NHH. 