Your question is in the "Community Feedback" space where few will see it. To get better responses, you might follow the instructions here to move your question:
Thank you for your post!
As beverly suggested, I'm going to move this thread from the FileMaker Community Feedback Space (which is specifically for input on the Community itself) to the Discussions Space where you should receive more views and potentially more feedback on this topic!
This is a summary (Count) of the zip code field. Summary fields can be used in a report (placed in a Sub-Summary part & sorted by the Zip Code field. You don't even need to have a "body" part in this type of list layout. Just put the Zip code field and it's summary field into the Sub-summary part.