An easy way to gather this information on a specific Account is by going to their Account Summary
Click Accounts in the left-hand side bar
Search for the desired Account
Click on the Account Name
The Booking tab (highlighted below) will tell you how many Bookings this Account is associated to.
Please note: this is all Bookings, regardless of status or date.
If you'd like to see more detailed information, the Booking List Report is a great option! By exporting to HTML with the get a more detailed rundown:
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