The number of reported sexual offenses on the subway has surged over the past three years, from 1,031 in 2012 to 1,356 last year, data showed Wednesday.

According to the data released by the National Police Agency and Seoul Metropolitan government, the number of physical sex crimes, such as groping, stood at 725 while 631 people were reported to the police for intrusive photography last year.

The highest number of sex crimes occurred on Subway Line No. 2 at 457 last year, followed by line Nos. 4 and 7, both at 146. A total of 119 sex crime cases occurred at Sadang station, the highest number of all stations in Seoul.

About 330 reports were made against people in their 30s, who made up the largest group, followed by suspects in their 20s at 304 and 40s at 174.