Fast-food giant McDonald's said today that revenue at its restaurants that have been open at least 13 months fell 1.8 percent in October — the first time it has suffered a month-to-month decline in that key indicator since April 2008, according to BloombergBusinessweek .

As The Associated Press says , "the figure is a key metric because it strips out the impact of newly opened and closed locations. It's a snapshot of money spent on food at both company-owned and franchised restaurants and does not reflect corporate revenue."

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