Sorry I cannot answer this directly, but I can tell you this:
I brought my PS3 over to my Moms place one week while I was house sitting. I played MW3 (I know you asked about BO2), but I blew her monthly usage cap. She has a 20G monthly allowance...
It was not all me.. but I got it up there.
I typically use about 1-3G/Day playing online (lower end during the week, higher end on the weekends)
Not a direct answer, but hope it helps.