The economy grew a real 1.6 percent in the October-December period from the previous quarter, revised downward from the initially reported 1.7 percent expansion, due mainly to a fall in inventories, the government said Wednesday.

The expansion, measured in terms of gross domestic product, translates into an annualized growth of 6.4 percent, revised downward from the earlier reported 7 percent growth, the Cabinet Office said.

Although the margin of growth was curtailed, the figure still marks the fastest expansion since the April-June quarter of 1990, when GDP surged a real 2.5 percent, and the fourth consecutive quarterly rise in real terms.

The downward revision was a surprise as most private think tanks had forecast the government would revise the GDP slightly upward in the October-December period, considering the recent growth in capital investment.

Despite the slight downward revision, the government sounded upbeat about the data.

A drop in inventories was mainly attributable to brisk shipments of industrial robots and semiconductor equipment.