Nearly 2.73 billion passengers used subway lines run by Seoul Metro last year, the subway operator said Tuesday.

On average, some 7.47 million people used Subway Line Nos. 1 to 8 daily as well as the second and third segments of Line No. 9 (Eonju Station to VHS Medical Center Station).

Gangnam Station on Line No. 2 was the busiest subway station, with a daily average of 141,597 passengers.

Hongik Univ. Station and Jamsil Station, also on Line No. 2, were the second-and third-busiest stations, with 129,199 and 118,244 passengers, respectively, on average daily.

Dunchon Oryun Station on Line No. 9, was the least busy -- used by 1,529 people on average daily. It was followed by the Dorimcheon and Sindap stations on Line No. 2, with 1,979 and 2,048 passengers, respectively.

Songpa Station on Line No. 8 saw the sharpest increase in passengers compared to the previous year.

The average daily number of passengers using Songpa Station jumped 73 percent from 2018 to 14,982 last year, thanks to a newly opened large apartment complex in the area called Helio City.

However, Namtaeryeong Station on Line No. 4, Olympic Park Station on Line No. 5 and Sports Complex Station on Line No. 2 saw their number of passengers drop by 42.6 percent, 22.3 percent and 15.5 percent, respectively.

Line No. 2 was the busiest subway line, transporting over 2.22 million people on average daily, more than double the number of people that used Line No. 7 (1.04 million), the second-busiest line.

By Kim So-hyun (sophie@heraldcorp.com)