By John S. McClenahen In August, the most recent month for which data are available, the Conference Board's leading economic index for South Korea was unchanged at 121.9 (1990=100). In both June and July, the leading index declined 0.1%. The value of machinery orders and monthly hours worked both declined in August. "The leading index increased very rapidly through the first quarter of 2004, declined in the second quarter, and has now been essentially flat in the last three months," says the New York-based business research group. "At the same time, however, the weakness in the leading index has become more widespread."