DC kicks off the year with a new sales record: Average numbers of the DC Universe line dropped by 21% in January, to 24,321 — the lowest number in the history of these charts, by about 4,000 units.

Traditionally a weak month in the comic-book market, January 2011 was even more of a downer than usual for DC. With only five titles selling above the 50k mark, average comic-book sales of the company at large fell to 21,922, the lowest figure since March 2009, while average Vertigo sales clung to the 10,000-unit mark, as they’ve done for the last three years.

The poor January performance of the DC Universe line comes thanks to three different kinds of erosion. First up, DC failed to get Green Lantern, Batman Incorporated and The Flash out of the door, three of its major titles, while a fourth one, Batman: The Dark Knight, was still late from December.

Second, DC is looking at a whole range of failing titles: Out of the 43 ongoing monthly DC Universe series currently on sale, eight have been marked for cancellation and won’t be around come June 2011. That’s almost 20% of the imprint’s regular output. And there are eight more — Doc Savage, The Spirit, T.H.U.N.D.E.R. Agents, Jonah Hex, Booster Gold, Power Girl, Zatanna and Gotham City Sirens — that look less than healthy and sell fewer copies than some of the ones that have already been axed.

At the tail end of the spectrum, finally, six former WildStorm titles were absorbed into the DC Universe line in January, where they end up being the six lowest-selling books and dragging down the average. (If WildStorm were still around, this would be another new low for them: The six books, one of which missed the charts altogether, have average sales of less than 4,000 units.)

So, for better or ill, 2011 is set to be a year of transition for DC, with some heavy lifting in the company’s periodical line.

See below for the details, and please consider the small print at the end of the column. Thanks to Milton Griepp and ICv2.com for the permission to use their figures. An overview of ICv2.com‘s estimates can be found here.