Add the following statement to the Report
Select IfcRole, Count(*)
From document
Group by IfcRole;
And you will get a Result like this
There is a empty entry in the list. This is because some objects like Sketches or Groups don't have a IfcRole attribute. We can filter them out easily by changing the query to this
Select IfcRole, Count(*)
From document
Where IfcRole IS NOT NULL
Group by IfcRole;