Used verses allocated storeage in reports

When storage is assigned to VM's we assign storage so that it can grow as necessary.  However when a report is run the total assigned storage shows as being "used".

For example, if a disk is say 100gig in size and we allocate 75gig for a VM and that particular VM is only using 10gjg, the report would show up as being 75% used, but in fact the VM is using only 10gig which amounts onjly 10% of the disk storage.

Is there a way so that the REAL amount of disk storage is being shown in the report rather than the allocated storage amount.