What's the max concurrent calls that my asterisk has used?

Hi guys. I’m trying to figure out if there’s a way to determine from the asterisk logs the maximum number of simultaneous calls that the box has actually experienced. I am aware of how to set a maximum, and all the searches I have attempted have given me this information. I want to know if I’m paying for more concurrent call sessions than my company actually needs. Any help would be appreciated.

I am running Asterisk 1.4.22 with Trixbox.