The easiest way to do this is to create a sub-summary report. Create a new layout and add a subsummary part that sorts or breaks by the Client field. Place the Client field and a summary field that counts the Client field into the subsummary part. There is no need for a Body part as it will show detail you aren't interested in. You can view the report in browse mode if it is sorted by Client and displaying as a list. In preview mode, you just need to sort by Client.