NEW YORK (Reuters) - Former New York City mayor Ed Koch died on Friday at age 88 after a year of repeated hospitalizations, a spokesman for Koch said. As mayor from 1978 to 1989, the forceful, quick-witted Koch, with his trademark phrase "How'm I Doing?," was a polarizing figure and the city's constant promoter. Koch died at about 2 a.m. (0700 GMT) at New York-Presbyterian hospital, the spokesman for Koch said. Koch was credited with lifting New York from crushing economic crises to a level of prosperity that was the envy of other U.S. cities. ...