Following on the heels of the news last week that magazine advertising revenues were down last quarter (big surprise there), we then learned that BusinessWeek was up for sale. Could there possibly be some correlation?

Well, see for yourself. Nat Ives at AdAge.com has put together this depressing chart, marking how ad sales at business magazines — BusinessWeek, Forbes and Fortune — have plummeted over the past decade.

“Since 1999, the number of ad pages the three major business titles booked for the first half of the year has fallen by 64 percent,” Ives reports. “In 1999, BusinessWeek, Forbes and Fortune carried 6,193 ad pages in the first six months of the year. In 2009, that number shrank to 2,204. That means it’s likely the final year tally for the three won’t crack 4,500, a benchmark that all three managed to surpass on their own in 1999.”

Ouch.