The Group Sales Revenue report provides revenue information about all of your group sales reservations whether or not they've been checked in.

This report does indicate which groups are checked in with a green check mark to the left of the Group Reservation name: 
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In the example above, the reservation arriving on 2/10 is checked in. The reservation arriving on 3/1 is not checked in since there is no green check mark. 

On this report, you can view summary information such as order totals, refunds, and balances owed. You can also view information about individual reservations such as the arrival date, number of visitors, order total, and paid amount. To view more details about a reservation, click its link under Reservation.