First of all, go here:
[URL="http://www.belloflostsouls.net/2013/07/academic-study-of-tabletop-wargamers.html"]Academic Study of Tabletop Wargamers: The Results are in! Part 3: Wargames and Armies We Play[/URL]

Then look at the chart of what armies players own.

Attachment 4320

Attachment 4319

Interesting stuff.

Here's my question - Why is the delta as a ratio between the most popular and least popular army in WFB less than half what it in in 40K?

WFB: Most popular: Warriors of Chaos: 306
WFB: Least popular: Tomb Kings: 149

40K: Most popular: Space marines: 1075
40K: Least popular: Sisters of Battle: 293