According to Facebook’s latest annual report, “In the fourth quarter of 2017, we estimate that duplicate accounts may have represented approximately 10 percent of our worldwide MAUs (Monthly Active Users). We believe the percentage of duplicate accounts is meaningfully higher in developing markets such as India, Indonesia, and the Philippines, as compared to more developed markets.”
For those wondering what 10% of Facebook’s monthly active users is equivalent to, last we heard Facebook was boasting about 2.13 billion monthly active users, which means that 10% of that is roughly 200 million. That being said, not all fake/duplicate accounts are nefarious in nature, with some creating accounts for their pets, or where some are misclassified accounts, and so on.
It is possible that the number of fake/duplicate accounts could be higher than what Facebook is reporting as trying to figure out a fake account could be difficult.