BEIJING — China has decided to raise the basic old-age pension for retirees in 2017, a 13th straight year of pension rises.

Starting from the beginning of this year, the average monthly payment for pensioners of enterprises, government agencies and public institutions has been lifted by 5.5 percent from the 2016 level, according to a circular issued by the Ministry of Human Resources and Social Security and the Ministry of Finance on April 13.

The increase was milder than the 6.5-percent pension rise last year.

Authorities attributed the slower increase to moderating economic growth and a rapidly aging society, which imposes a heavier burden on the country’s pension funds.