South Korea's economy posted its second-biggest monthly exports in June, thanks to solid demand for semiconductors, ships and petrochemicals, a government report showed Saturday.

Exports, which account for about half of the export-driven economy, increased 13.7 percent from a year earlier to 51.4 billion U.S. dollars in June, according to the Ministry of Trade, Industry and Energy.

It was the second-largest monthly figure since the country began compiling the data, the ministry said. The record high number was 51.6 billion dollars tallied in October 2014.

The overseas shipments posted a double-digit expansion for six months since January, while maintaining an upward momentum for the eighth consecutive month.

Imports advanced 18 percent over the year to 40 billion dollars in June, sending the trade surplus to 11.4 billion dollars. The country's trade balance stayed in black for 65 months in a row.

For the first six months of this year, the exports amounted to 279.4 billion dollars, up 15.8 percent compared with the same period of last year. Imports surged 21 percent to 233.6 billion dollars in the same period.

The trade ministry estimated that the South Korean economy would registered 545 billion dollars of exports for the whole year of 2017, with imports worth 463 billion dollars.

If realized, the economy's combined trade of exports and imports would top 1 trillion dollars in three years.

On a daily basis, the exports in June averaged 2.24 billion dollars, up 13.7 percent from a year earlier. The daily average exports kept rising for the seventh straight month.

By product, semiconductor exports reached the monthly high of 8.03 billion dollars in June due to stable memory chip prices and demand for chips used for personal computers and servers. The chip shipments kept growing for nine months in a row.

Display panel shipments logged a double-digit increase for the seventh straight months amid rising demand for OLED panels and higher LDC panel prices.

Exports for petrochemical products rose for nine months in a row as companies expanded production capability amid higher export prices.

Oil product exports kept rising for the eight consecutive month amid higher product prices, while general machinery exports registered the third-biggest monthly exports due mainly to exports of large-scale nuclear reactor parts to the United Arab Emirates (UAE).

Ship exports posted the record monthly high in June thanks to 26 shipbuilding orders, including three high value-added ships.

Automobile exports rose for the fifth straight month on demand for environmentally-friendly vehicles, with those for textile products rebounding in three months on demand from Southeast Asian countries.

Exports of telecommunication devices such as smartphones tumbled 35.9 percent last month as local companies increased production in overseas factories.

Consumer electronics exports also plunged 25.7 percent amid increased production in overseas factories that offset strong demand for locally-made washing machines and air conditioners.