Jul 23, 2012 (Dow Jones) -- The world refined copper market was in deficit by 384,000 metric tons in the first four months of 2012, a substantial increase from the same period last year, according to the latest data from the International Copper Study Group.

The 2012 deficit for the January-April period compares with a 26,000-ton deficit for the same period a year earlier, the group said Friday.

World refined usage in the period totaled 6.948 million tons, while output totaled 6.564 million tons, it said.

The deficit grew largely as a result of higher Chinese demand, it said.

"During the first four months of 2012, world apparent usage of copper grew by 10% compared with that in the same period of 2011, principally owing to strong growth in Chinese apparent usage, as world usage ex-China declined by 2.5%," it said.

China's apparent consumption rose 33% on year in January to April and represented 43% of world usage, it said.

On the supply side, world mine production rose by 1.8% compared with the same period last year. Refined metal production rose by 4.5% compared with the same period in 2011.

Refined production rose in China, Japan and Africa but declined in Chile and the U.S.

The market deficit in April totaled 104,000 tons, slightly narrower than 134,000 tons the previous month.

Three-month copper prices are trading around $7,470/ton on the London Metal Exchange, down 1.0% from Friday's settlement and 1.7% lower since the start of the year.