(BUSINESS INSIDER) — For years, Subway ruled fast food.
But the sandwich's chain future is looking increasingly bleak.
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Subway's U.S. sales last year fell by 3%, the most of any of the top 25 fast-food chains, Drew Harwell reports at the Washington Post.
Subway also fell two spots to become the third-most-popular fast-food restaurant for the first time in seven years.
The fast-food chain's problems can be traced back to two mistakes ...