We have made a few updates to the sales graph at the top of the Dashboard page. 

The data shown on the graph has not changed, you are still looking at the total transactions per day (items sold, minus discounts, excluding taxes), over a time period. When you click on a specific data point, we are now linking to a list of those transactions for that day. 

This is much more clear since the data point in the graph will match the total you see in the Transaction report for that day.

Before the links were taking users to a Registration report, and the transactions wouldn't necessarily match what was sold at the time of registration. If changes were made (upgrades, downgrades etc) after the time of registration, they wouldn't be reflected in that registration report.