The population of Seoul declined for the fifth straight year in 1997 and the number of males is steadily outnumbering females, a demographic tally showed yesterday. The city's analysis of registered residents in Seoul said there were nearly 10.39 million people living in the capital last year, 0.77 percent less than the year before. The figure marks the fifth consecutive drop since the city in 1993 registered the first ever decrease in the number of its dwellers in 36 years. The rate of reduction was 1.16 percent in 1994, 1.88 percent in 1995 and 1.19 percent in 1996.