TOKYO, Feb. 22 (Xinhua) -- Tokyo stocks opened lower Friday tracking U.S. shares retreating overnight after weak economic data sparked concern over the health of the U.S. economy.

As of 9:15 a.m., the 225-issue Nikkei Stock Average dropped 88.08 points, or 0.41 percent, from Thursday to 21,376.15.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, lost 7.62 points, or 0.47 percent, at 1,605.88.

Marine transportation, wholesale trade, and nonferrous metal-linked comprised those that declined the most in the opening minutes after the morning bell.