Blast, can't see it at work. (If anyone could be a dear and download it and put it somewhere "safe," that'd be great.) Ironically, the filter here blocks GW's investor website, but not their core website. Sometimes I wonder who's setting the rules for that thing...
Anyway, on topic...
It's not just the 40K rulebook, which was $85 so a hefty sum of money per purchase. Is this for the second half of the year, or first half? If second half, it should catch even more of the 40K rulebook sales, plus the two campaigns, all that End Times stuff, Orks, Space Wolves, Grey Knights, Dark Eldar... Holy smokes, if you're down on sales despite all that stuff coming out, there's a problem. But even for the beginning of the year, you have the IG, Tempestus, Knights (which should have continued to sell as the year went on), Escalation and Stronghold Assault likely (I think they were late 2013 releases so might have moved more in early 2014), Dwarfs, Tyranids, probably more stuff I'm forgetting.
For the entire year, they swapped out the underperforming (gee, I wonder why?) $10 monthly White Dwarf with a $12 monthly Warhammer Visions and $4 weekly White Dwarf, so if people got all of those, that's $28/month at least. Of course, given the number of copies I see ending up in the trash (where they toss them, instead of trying to re-sell them), it seems they're not moving as well as expected, so the whole restructuring of WD to try to get more money for less work doesn't seem to have worked so well. Wow. Who could have seen that coming?