North Korea's trade with China surged more than 60 percent last year, a sign of deepening dependence on Pyongyang's biggest ally.
South Korea's Statistics Korea said Thursday in an annual report that North Korea's exports and imports with China reached $5.63 billion in 2011, up 62 percent from $3.47 billion in the previous year.
China accounted for 70 percent of North Korea's annual trade in 2011, higher than 57 percent in 2010.
Statistics Korea said the volume of North Korea's annual trade reached $8.03 billion last year, up 32 percent from 2010.
While Pyongyang's economic exchange with Beijing has been on the rise since 2009, its trade with Seoul, North Korea's second-biggest trade partner after China, has declined. About 20 percent of North Korea's overall trade was with the South in 2011.
The national statistics office releases an annual report on North Korea's economy, energy, trade, population and natural resources based on figures from various agencies at home and abroad. It releases the previous year's data at the end of the following year. The figures for 2012 will become available toward the end of 2013.
North Korea's trade data was gathered from official statistics figures in overseas countries through KOTRA, the Korea Trade-Investment Promotion Agency, the office said.
The office said North Korea's population is estimated at 24.3 million as of 2011, about half of South Korea's 49.8 million. Its economy expanded 0.8 percent in 2011 over a year earlier, while South Korea's economy grew 3.6 percent.
Its gross national income per capita stood at 1.33 million won ($1,241), compared with South Korea's 24.92 million won.