IPSec Incoming Data bar

If we go to ipsec monitor we can see the active ipsec tunnel and for every tunnel there are incoming and outgoing data traffic.

My question is in the incoming and outgoing data there are bar indicating the traffic. How much data in incoming or outgoing data so the bar will full?

The outgoing data 269.24GB the bar maybe only 25% from full, so what calculation to determinte the full bar?