The number of blood donors in South Korea jumped nearly 20 percent over the past four years on the back of the rising participation of teenagers and twenty-somethings, the health ministry said Monday.

About 3.08 million people donated blood last year, up 17.8 percent from 2.61 million tallied in 2011, according to the Ministry of Health and Welfare.

Out of the total contributors, 1.33 million people, or 43 percent, were in their 20s and 1.05 million, or 34 percent, were teens.

Those in their 30s accounted for 12.4 percent, followed by people aged 40 or over taking up a combined 10.9 percent.

The ministry said the number of donors has increased in all age groups, except for teenagers which have been on a steady decline due to the low birth trend in South Korea, over the cited period.

The country's fertility rate, or the average number of babies that a woman is projected to have during her lifetime, stood at 1.24 in 2014, one of the lowest in the world. (Yonhap)