A survey shows optimism is growing over inter-Korean trade next year.

The Korea Development Institute on Monday said its study on inter-Korean trade prospects showed an expectation index of 141 among companies and 158 among experts, both the highest since November 2003.

The survey was conducted between November 14th and 18th on 147 trading companies doing business in the North and 35 experts. The rating system ranges from zero points as the lowest to 200 as the highest with a benchmark of 100.

Some 47 percent of the firms said they will expand their inter-Korean business next year, while 42 percent expected no change.

The institute's chief researcher on the North Korean economy, Kim Sang-ki, said the survey reflects a general improvement in the environment for inter-Korean trade.