BANGKOK - Thailand's exports plunged by more than a quarter in May as the economic downturn continued to hamper foreign demand for goods, the government said Friday.

Exports, which account for 70 percent of the country's economy, fell by 26.6 percent year-on-year in May, the commerce ministry said.

It was the seventh consecutive month to see a fall.

"Exports dropped in every sector, including agriculture which tumbled 26.9 percent and the industrial sector which fell 25.2 percent," said Siripol Yodmuangcharoen, permanent secretary of the commerce ministry.

He said the main reason for the drop was declining demand in key overseas markets and increased competition.

The slump came despite Thailand's exports to new markets - including Africa and the Middle East - expanding by 17.8 percent.

Exports fell by an average of 34.5 percent to its major export markets - the nine other members of the ASEAN group, Japan, the European Union and the United States.

Due to the ongoing fall, the ministry revised down its economic growth target for the whole of 2009, forecasting the economy would contract by 15 to 19 percent, from its earlier forecasted growth of between zero to three percent.

Thailand saw a trade surplus of 2.4 billion dollars in May as the kingdom imported fewer goods than it exported.

For the first five months of 2009 Thailand registered a trade surplus of 10.0 billion dollars.