<prompt> Translate the following text to Swahili9 billion pieces respectively, and assuming that First-Class advertising mail volume has not changed between 1997 and 1998, we obtain the following figures for FY 1998: a 91.  <response>: Kwa mfano, ikiwa idadi ya barua za matangazo ya kwanza hazijabadilika kati ya mwaka wa 1997 na 1998, tunapata takwimu zifuatazo kwa mwaka wa kifedha wa 1998: 