A report on the building of rural social security system was submitted Thursday to the ongoing session of the National People's Congress (NPC), China's top legislature, for deliberation.

Sun Wensheng, vice chairman of the NPC Agriculture and Rural Affairs Committee, said steady progress had been made in the development of rural social security system when delivering the report at the session of the NPC Standing Committee.

A total of 833 million rural residents, or 94 percent of the rural population, have joined the rural cooperative medical care system, up 2.5 percentage points from the beginning of this year, according to the report.

The rural cooperative medical care system, a government initiative implemented in 2005 that intended to make health services more affordable for the rural poor, had alleviated illness-caused poverty among farmers, it said.

The report said 320 counties, or 11.6 percent of the country's total, had been or would be approved to try a new rural social pension insurance system, which would benefit more than 15 million rural residents.

Under the pension system, senior rural residents will receive a monthly ole-age pension of varying amounts, which will be set by government according to the local income standards.

However, some local governments were financially challenged to implement the rural social security programs and only a relatively small percentage of migrant farmer workers were covered, Sun said.

The report was the result of a nearly four-month investigation conducted by the NPC Agriculture and Rural Affairs Committee.

Initiated in September, the investigation covered 17 provinces, municipalities and autonomous regions.