delinquency rates, prop mgmt company

I have a fourplex, maybe class C+. The neighorbood is mostly working-class families with young children. You’ll see a few rusted pickup trucks in that 'hood.

In the past year I’ve had 2 people skip on the lease, and had to evict 2 for non payment. I’ve only had 3 who consistently paid, and 2 of them moved out. I’m wondering if this rate of delinquency/skipping is normal or whether it says something about my property management company’s selection criteria or their service to tenants.

Can anyone shed light?