<prompt> Translate the following text to EnglishKwa hivyo, kwa sababu ya kuanguka kwa idadi ya posta, ni muhimu kuzingatia kuwa gharama za kipekee za kipekee za posta zinashuka kwa sababu ya kupungua kwa idadi ya posta kwa washindani.  <response>: We then examine the consequences of volume loss on postal systems in order to provide a measure of burden in terms of increases in average unit costs as volume is lost to competitors, or 