South Korea posted a trade surplus for the 40th month in a row in May as imports dropped at a faster pace than exports, customs data showed Monday.

According to the data by the Korea Customs Service, the country's trade surplus reached US$6.3 billion last month, down from $8.53 billion in April, but significantly higher than $4.97 billion a year earlier.

Exports dropped 10.9 percent on-year to $42.36 billion in May, while imports nosedived 15.4 percent to $36.06 billion. In May 2014, exports hit $47.57 billion, with imports standing just under $42.6 billion.

South Korea's trade account has been in the black since February 2012.

Last month exports of semiconductors rose 4.2 percent on-year, with shipments of wired telecommunication terminal products surging 52.7 percent. Deliveries of wireless communication products were also up 7.3 percent.

On the downside, car exports dropped 9 percent, with shipments of refined petroleum products and ships plunging 39.6 percent and 34.7 percent, respectively.

Outbound shipments of automobile parts and liquid crystal displays fell 8.9 percent and 3.1 percent, respectively.

By region, exports to Hong Kong grew 11.9 percent on-year, while sales in other parts of the world all declined.

Exports to China, South Korea's largest trading partner, were down 3.3 percent, with figures for the United States and the European Union declining 7.2 percent and 9 percent, respectively.

Shipments to Japan, Latin America and the Middle East were also down.

Imports of computer chips rose 9 percent on-year in May, followed by a 9.7 percent hike in information technology equipment.

Inbound shipments of crude oil dropped 25.8 percent, while imports of chemicals, minerals and steel dropped by double digits compared with the year before.

Imports from Latin America rose 18.2 percent, with numbers for China and the Middle East falling 7 percent and 33.1 percent, respectively. Products purchased from the EU, the United States, Japan and Australia all declined.

In the first five months of 2015, the country's cumulative exports reached $222.1 billion, down 5.7 percent from a year earlier, while imports came to $185.6 billion, representing a 16 percent drop.

In the January-May period, the country's trade surplus stood at $36.5 billion, much larger than the $14.5 billion in the black posted for the same period in 2014, according to the KCS data. (Yonhap)