<prompt> Translate the following text to SwahiliR97-1 rate case before the Postal Rate Commission, an econometric model became available for First-Class Mail with the characteristic that basic mail and workshared mail are treated separately.  <response>: R97-1 kesi ya kiwango cha posta kabla ya Tume ya Kiwango cha Posta, mfano wa kiuchumi ulipatikana kwa barua ya darasa la kwanza na sifa ya kwamba barua ya msingi na barua ya kazi ya kazi hutendewa tofauti. 