<prompt> Translate the following text to EnglishUwezo wa posta ni kipimo ambacho kina madereva mawili ya gharama ya nje kama vile sifa za kijiografia na demographic za maeneo yaliyohudumiwa na madereva ya ndani yanayoonyesha ubora wa huduma ya utoaji.  <response>: Postal density is a measure that contains two exogenous cost drivers such as geographic and demographic characteristics of the areas served, and endogenous drivers reflecting the quality of delivery service. 