A leading economic index for South Korea declined for the 13th straight month in June, indicating that the economy is expected to slow down in the coming months.

According to data from the Organization for Economic Cooperation and Development(OECD) on Monday, the composite leading indicator(CLI) of economic activity for South Korea marked 98-point-87 in June, down from 99-point-09 percent in the previous month.

The index rose to 101-point-95 in May of last year but slipped for 13 straight months since.

In particular, the index posted below the baseline 100 for six straight months since January.

The CLI is an indicator designed to provide early signals of turning points in business cycles around six to nine months in advance. A reading above 100 means the economy is expected to expand.