Making apps for Facebook? Better downgrade your list of potential customers by 83 million people. This week Facebook filed a 10-Q filing with the SEC, in which the company revealed details about duplicate and undesirable accounts.

Mashable did the math and figured out that 8.7 percent of Facebook’s accounts, or 83 million accounts, are fake. Check it out: “Of that 8.7%, 4.8% are duplicate accounts, 2.4% are user-misclassified accounts and 1.5% are ‘undesirable’ accounts, a.k.a. spam. The figure is a bit higher than the company’s previous estimates. In a March filing, Facebook claimed about 5% to 6% of its accounts — or 40.3 million to 50.7 million — were fake. The company also says it bans at least 20,000 accounts daily and estimates about 600,000 accounts per day are compromised.”

In the filing, Facebook reported that they have 955 million active users as of June 30th, which is up 29 percent year-over-year. In January, iCrossing predicted that by August Facebook would hit a billion users. Pretty close, but not quite, and even less so with the fake account.