Please hold while I pull up my previous explanation. Will edit when found. Eh. I found it. Was on a post and the person said .008 so I used that. Here is a potential explanation.
The %0.0008 number is an approximation and you seem to not understand how math works. You claim you have enough accounts banned alone to reach that number. See below
3a. Lets use a small number of just a million people. Multiply that by .0008 and you get 800 accounts. If you managed to even have that number, I fear for your mentality and sanity.
3b. The number of accounts is not static. So if we have a million players and 800 people get banned then we reach %0.0008, but say half of them make a new account to keep playing. 400 new accounts replace 400 of the banned ones. Now we still have 800 banned accounts, but the number of accounts is now 999,600 after they remade accounts as opposed to the 999,200 when they were banned.
So as bans go out, a new account may be made, therefore fluctuating the percent value of accounts banned v not banned.
You also have to consider smurfs and accounts to be sold.