    Sentence 4-Part ofthe reason for thé  difference 'in.pieces “per possible  delivery may be'due-to the fact that five.  percent: of possible .residential  deliveries «are ‘businesses, ‘and : it'-is  thought,. but not*known, ‘that ‘a.lesser  lpercentagé._ of: possible: deliveries ‘on.  rural routes are businesses.    Sentence 2: We alt know that the reason:  for’ a ‘lesser. percentage |’ of :possible  deliveries.” on: -:.rural.> routes... -béing:  businesses, is: because’ of. the-fact that  people prefer living in. cities rather. than  rural areas.