Interesting statistics. Very unexpected.
Mac 49%, Linux 25%, Windows 21%
These stats are consistent within 1-2% across all my web sites except the OS stats on one web site are different: on the Adult Life Training, Inc. site the OS stats are Windows 40%, Mac 38%, Linux 18% — possibly due the to lab computers home page being set to this web site and the tendency for beginners to prefer Windows until they learn a bit about how to work the computer. The Returning visitor stat on alt-fw.org is also higher (about half instead of about 1/4th) so that seems likely.
But on alt-fw.org and jdnash.org Mobile OS: iOS is 70% and Android is 30% with no Windows presence at all.
Return visitor is also high in this stat so it may be due in part to the free wireless we provide and an unusually high presence of Apple devices (near 100%) with organizational staff on the campus.