Hello Tobias,
Have you checked SAP note 1110822 (Workload collector: Reducing the size of aggregates)?
You can use the report SWNC_COLLECTOR_COMPRESSION from the note and select the checkboxes for:
[VC] WEB server
Technical name Description in ST03N
ACCOUNT, MANDT Account, client
HOST, PORT Host name, port
DESTINATION, PATH (*)Destination, Path/URL
ENTRY_ID (*) Report name, transaction name or name of the
background job
In addition, you should also re-aggregate the data that already exists in the database for your selected profile(s). To do this select the option "Schedule background program" (at the bottom) when running the report. Then the additional report SWNC_COLLECTOR_RECOMPRESS is scheduled to run once in the background.
For further information on these statistics you can also refer to the following link:
Also interesting: SAP note 1362295 (SWNC_COLLECTOR_RECOMPRESS: No compression, short runtime).
I hope this helps,
Cris