At first the math seemed hinky to me. Further reading informed me:
In the early years, Sohn donated blood only once every two months, the shortest interval required between donations under law at the time in consideration of a donor’s health.
But advances in medical technology made it possible to draw only key elements of blood, such as platelet and plasma, from donors while putting much less stress on their bodies. Unlike whole blood donations, only two weeks is required between platelet or plasma donations.
I am surprised that he started donating when blood could be drawn every other month. I started way back in the old days when you could donate only three or four times a year and I am nearly twenty years younger. Still, he has donated twenty-five times more than I have so I’m still impressed.
Foreigners can give blood in Korea but it takes a little work.