South Korea's trade with Vietnam has expanded 16.5 percent annually since the two countries implemented a free trade agreement in 2015, data showed Thursday.

The combined trade volume between the two countries reached $69.2 billion in 2019, compared with $37.6 billion posted in 2015, according to the Korea Customs Service.

South Korea and Vietnam implemented the FTA in December 2015, after kicking off their first negotiations in 2012.

Over the cited period, South Korea's trade with China, the top trading partner, grew 1.7 percent annually. Seoul and Beijing also implemented their free trade pact in a similar period with Vietnam.

South Korea's exports to Vietnam came to $48.2 billion in 2019, jumping 73 percent from four years earlier. The figure, however, fell 0.8 percent on-year as the trade feud between Washington and Beijing weighed down on the business sentiment around the globe.

In 2019, South Korea's combined exports slipped 10.3 percent on-year.

Vietnam was the third-largest export destination for South Korean goods in 2019, moving a notch up compared with 2015 by outpacing Hong Kong.

Exports of chips to Vietnam, in particular, grew sharply over the cited period, reaching $10.7 billion in 2019, compared with only $2.8 billion posted in 2015.

Outbound shipments of displays to the Southeast Asian country also gathered ground, reaching $7.9 billion last year, compared with $254 million in 2015.