According to Yonhap News,

(SEOUL = Yonhap News) Inter-Korean trade has gradually been returning to normal levels following the reopening of a joint industrial park in North Korea's border city of Kaesong, data showed Monday.

According to the data by the Ministry of Unification and the Korea Customs Service, two-way trade between South and North Korea amounted to US$155.03 million last month.

It is equivalent to 87.2 percent of the total bilateral trade in the same month last year and 94.4 percent of the average monthly trade volume in 2012, the data showed.

The total trade volume was attributed solely to the Kaesong Industrial Complex, as inter-Korean trade is limited to the factory zone, with all other economic exchanges being banned since May 2010 due to North Korea's sinking of a South Korean warship in March of that year.

The trade has been on the rise since September when the joint park reopened following a halt in April amid high tensions on the Korean Peninsula. The figure for October was $152.16 million.

The complex, the last symbol of South-North economic cooperation, combines South Korean capital and technology with cheap North Korean labor to produce clothes, utensils, watches and other labor-intensive goods.

More than 44,000 North Koreans work for the 120 South Korean firms operating in the park, and the project serves as a major legitimate revenue source for the impoverished communist country.

The two Koreas plan to hold working-level talks on Thursday to discuss ways to upgrade the factory park, including attracting foreign investors.