Discrepancies between Call Log and Performance Reports

I'm seeing a discrepancy between the number of inbound calls in the performance report and what is in the call log. For example, in looking at a particular day, the call log shows 69 inbound calls whereas the performance report is 58. There is a 8-15 call discrepancy for each day that I've looked at.

I've looked at the call logs to see if I can isolate what calls aren't being included, but the performance report for the queue don't provide enough detail to figure out which calls are being filtered out.