A latest census released Tuesday showed that about one fourth of Shanghai permanent residents were aged at 60 years or older as of 2010.

1/4 Shanghai residents aged above 60.[File photo]

The census, which was conducted last year by the Shanghai Municipal Commission of Population and Family Planning, showed that 3.31 million permanent residents, or 23.4 percent of the city's total, were older than 60 years.

The ratio was only 19.6 percent in 2005.

In 2010, the city had a total population of over 23 million, including 14 million permanent residents and a floating population of 9 million who had lived in Shanghai for over half a year, according to the census.

The floating population increased by 5.5 million in the 10 years to 2010 as more rural migrants move to the country's financial and business hub in search of higher-paid jobs and presumably better life.