Customer Concentration and government contracting breakdown

When talking about customer concentration, specifically in the government contracting space. Do you consider the whole government as one customer or do you break it down by governmental agency served? For example, if your client mix is 50/50 government and SMBs. But breaking it down further you would see that no one agency has a high concentration in your client mix. I’m leaning towards looking at it broken down by govt agency. Has anyone had this come up?