The average monthly salary for China's 158.63 million migrant workers rose 21.2 percent in 2011 from a year earlier, the National Bureau of Statistics (NBS) said Friday.

An NBS survey of the country's migrant workforce showed that the number of rural migrants working outside their hometowns increased 3.4 percent year-on-year last year, while their wages rose to an average of 2,049 yuan (about $325.24) per month.

The country had a total of 252.78 million rural workers as of the end of last year, up 4.4 percent from a year earlier, the NBS said.

Of the total, 65.4 percent of the rural labor force chose to work in the country's comparatively well-off eastern regions last year, down 1.5 percentage points from the previous year.

The data also showed that more rural workers chose to work in their home provinces, up 10.1 percent from a year ago and accounting for 52.9 percent of those who work outside their hometowns.