Nine Inch Nails [ tickets ]' latest album, the sprawling, 36-track instrumental set "Ghosts I-IV," has garnered more than 750,000 downloads since being released over the web last week.

The two-hour set, which was composed and recorded by bandleader Trent Reznor over a 10-week period last fall, has amassed a total of 781, 917 transactions, including both free and paid downloads as well as orders for the physical version of the album, since being released March 2 via the band's website," according to the group's management team.

"These figures represent the most relevant and contemporary metric for measuring how Nine Inch Nails' music is reaching its fans," NIN manager Jim Guerinot said in a press release, which added that the band has thus far raked in more than $1.6 million in direct sales. The statement added that NIN's label, The Null Corporation, will not be releasing to Nielsen SoundScan the traditional sales figures that are normally used to tabulate chart position by various sources like Billboard.

The group announced surprise plans for the release earlier this month after Reznor teased fans for weeks with the possibility of a forthcoming mystery project. "This music arrived unexpectedly as the result of an experiment," the singer posted on the band's website on March 2. "The rules were as follows: 10 weeks, no clear agenda, no overthinking, everything driven by impulse. Whatever happens during that time gets released as ... something.

"The end result is a wildly varied body of music that we're able to present to the world in ways the confines of a major record label would never have allowed--from a 100% DRM-free, high-quality download, to the most luxurious physical package we've ever created."

In addition to the basic download (the group is allowing fans to download the album's first nine tracks for free, or all 36 for $5), the band simultaneously released the set in a variety of deluxe packages, including the $300 "Ultra-Deluxe Limited Edition," which was limited to a run of 2,500 copies and sold out almost immediately, according to NIN.

The group is still offering the following packages through the site: $10 for a two-CD set housed in a six-panel digipak with a 16-page booklet; and $75 for a deluxe edition package that features a large fabric slipcase containing two embossed, fabric-bound, hardcover books, the two audio CDs, as well as a DVD containing multi-track versions of all 36 tracks.