What's the rate on late fees?

Okay. So. I've been a cox customer for somewhere in the ballpark of nine months. Never been late with a payment. Not really planning to. I see all this talk about late payments and how paying a portion of your bill will lower the fee and it made me curious.

What is the calculation/percentage on late fees?

Is it a fixed amount like 5 dollars for every hundred late? 5 dollars a day? A flat fee of 30 or something until your next bill comes out?

At this moment it's just general curiosity but I'd like to find out now before, fingers crossed, I should actually need to know.

Thanks in advance,

Me <3