question about call queue member historical report

Apologies, but I've looked through the power pack articles regarding this and haven't been able to find this answer. In the Call Queue Member Historical Report there is a column marked 'Total Inbound Calls'. In my case every member of this call queue has a wildly different number there. I guess I'm not sure why this number would be different as all are in the same call queue. These are not extensions that anyone dials directly. Any clarification would be appreciated. Thanks.