Japan's economy grew slower than initially estimated in the July-September period due to weaker-than-expected corporate capital spending, the government said Friday.Gross domestic product (GDP) expanded at an annual 5.6 percent pace in the third quarter, a downgrade from the preliminary figure of 6.0 percent released last month, according to the Cabinet Office.However, the economy still marked the first expansion in three quarters, as the country recovers from the March 11 earthquake and tsunami.On a quarterly basis, GDP grew 1.4 percent in the three months ended September 30 from the previous quarter compared with the preliminary estimate of a 1.5 percent rise.Corporate capital spending, a key pillar of domestic demand, slid 0.4 percent from the April-June quarter, revised down from a 1.1 percent growth in the preliminary data. Private consumption, which makes up some 60 percent of Japan's GDP, rose 0.7 percent, slower than a 1.0 percent increase in the previous estimate.The world's third-biggest economy fell into a slump following a magnitude 9.0-earthquake and tsunami on March 11, which left nearly 21,000 people dead or missing, and crippled the Fukushima Daiichi nuclear plant. The twin disaster also destroyed many factories in northeastern Japan and caused nationwide parts supply problems, especially for automakers.A Cabinet office official said Japan's economy is still picking up despite the revision."But we need to carefully monitor the impact of the yen's rise and the eurozone debt crisis on the country," he told reporters.GDP is the total value of goods and services produced domestically. Real GDP is adjusted for price and seasonal variations.