Ignoring certain cells in AVERAGE formule

Hi all

I have a team of sales guys and want to average their conversion rates through the day.

But I am having difficulty working out how to INCLUDE those who are working but on 0.00% and EXCLUDE those that are on 0.00% because they are NOT working.

I have attached a sheet I hope I am making some sense!

Basically I need to include all the Agents who have a customer count above 0 and exclude anyone that doesnt.