<prompt> Translate the following text to EnglishUfaulu wa utoaji wa huduma ya posta unategemea mapato ya barua zote zilizotolewa, na haiwezekani kwamba skimmers za cream zinaweza kukamata aina zote za barua.  <response>: Postal Service delivery profitability depends on the revenue for all mail delivered, and it is not likely that cream skimmers could capture all categories of mail. 