Japan's tertiary industry activity index rose during the April-June quarter to its highest level in four years, the government said Friday, reinforcing the view that the country's economic recovery has taken root among nonmanufacturers.

The index for the quarter rose 1.6 percent from the previous quarter to a seasonally adjusted 104.3 against the base of 100 for 2000, the Ministry of Economy, Trade and Industry said in a report. It was the biggest quarterly gain since 1.3 percent in the same quarter of 2000.

The index of all industrial activity, a supply-side gauge of economic growth, came to a seasonally adjusted 102.3, up 1.8 percent, and the highest level in four years, according to the report.