This is one outlet's own report from Forbes — the article as it was filed.
Taco Bell Visits Dropped Over 30%—More Than Initially Reported—Amid Outbreak

Topline A cyclospora parasite outbreak possibly tied to lettuce used by Taco Bell and many others appeared to deliver a blow to the chain's customer traffic—significantly more than was originally reported—as the stock of its parent company, Yum! Brands, fell drastically from a five-month-high earlier this month.
Taco Bell's customer visits on July 17 were roughly 31% below the chain's average Friday traffic level for the year to date, according to Placer.ai , which tracks location activity through mobile devices.
The hit was initially reported to be about 19%, but Placer.ai says early coverage underreported the impact to the restaurant.
