SEOUL - Four out of 10 surviving South Koreans whose families were separated by the 1950-53 Korean War are in their eighties and older, data showed Thursday.

The survey, conducted jointly by the unification ministry and the Red Cross, polled a total of 66,611 South Koreans whose families are in the Democratic People's Republic of Korea (DPRK).

The ministry, which oversees inter-Korean affairs, puts the total number of such people at 81,800.

South Korea and the DPRK have held 17 rounds of reunions for war-split families on both sides of the border, with the last round held in 2010.