The estimate of 80 million users comes from The Document Foundation. It’s very conservative, based on unique IPs of pings for updates. In their annual report for 2013, LibreOffice claimed 100 million users based on download numbers.
Then there is Canonical distributing Ubuntu GNU/Linux. In 2012, Shuttleworth estimated that most users of GNU/Linux had installed it themselves but that they were gearing up to ship Ubuntu GNU/Linux on 20million PCs annually from OEMs. In 2013, Ubuntu Forums had a break in and 1.8 million hashed passwords were stolen. That supports the idea that Ubuntu GNU/Linux has tens of millions of users. In 2014, Canonical claimed 20 million PCs had shipped from OEMs in 2013/2014 with Ubuntu GNU/Linux.
Then there is Dell with ~1K stores in China and India. They are likely selling most of those Ubuntu GNU/Linux PCs.
Then there is Linpus, dealing with OEMs directly in China where most PCs are made.
Then there is Europe with governments like France pushing FLOSS and India, making its own distro for use in government and business.
GNU/Linux and FLOSS now have many promoters besides us computer-geeks and it shows. FLOSS has become a major player in IT on a global scale whether it wins one PC at a time or takes over whole governments.