BEIJING, May 16 -- China's courier sector expanded in April, with significant growth in delivery scale, according to an industry index released by the State Post Bureau on Friday.

The express delivery development index stood at 443.2 in April, up 6.5 percent from the same period last year, according to the bureau.

The sub-index for development scale rose 15.7 percent year on year. The sub-index for service quality grew 1.5 percent from a year earlier, and the sub-index for development capacity increased 1.4 percent year on year.

The index is compiled based on data from major logistics firms operating delivery services. It reflects overall business activities and trends in the country's courier sector.