China’s migrants numbered 247 million, or 18 percent of the total population, at the end of 2015, according to an official report released on Oct 19.

Among migrants — referring to those who have left their hometowns to live and work elsewhere — the elderly population has continued to increase, now accounting for 7.2 percent of the total migrant population, said the report by the National Health and Family Planning Commission (NHFPC) of China.

Wang Qian, head of the Department of Services and Management for Migrant Population of the NHFPC, said motivations for elderly people to migrate mainly include looking after younger generations, living in more desirable places, and migrating from rural areas to cities for work.

Elderly migrants who look after their grandchildren account for 43 percent of the total elderly migrant population, the highest proportion among the age group, according to Wang.

According to the report, the migrant population will remain above 200 million through 2020 as a result of rapid urbanization in China.