The Network Report provides a historical view of average network speeds on each network interface. This report is invaluable when diagnosing network performance issues.
If your system does not have this app available, you can install it via the Marketplace.
You can find this feature in the menu system at the following location:
The Network Report provides the average speed received and transmitted on each network interface. The adjacent screenshot comes from a small office environment with very modest network requirements. The spikes come from large downloads and video streaming.
If you see network speed clamped at the maximum all day long, a plan of action is recommended. Increasing network capacity is certainly one option, but taking control over network usage is another way forward.