Insolvencies across the wider economy, including other sectors such as construction and manufacturing, were down 3% on the previous year.
This adds weight to suggestions that recent official figures showing that gross domestic product (GDP) declined 0.7% in the quarter may be overestimating the severity of the double-dip recession.
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Mr Kim has made two recent visits to China.
The study looked at the development of 422 children over the course of eight years.
The president said they will come into force if China refuses to change its practices.