Related Resources:
Product Stats: How to group categories
The data that you see on the Product Stats page is today's data ONLY. As your products begin to sell throughout the day you will notice more products appearing.
In order to see more days you will have to use the Smart Search feature to change the date(s). Go to the Main Menu > Product > Product Stats use the Smart Search filter and change the date(s).
How do I see a date range? Within the Smart Search feature select desired dates in the Purchased Date From and To fields, then click the green "Search" button to view results: