The rental fees in commercial facilities at Incheon International Airport have increased nearly 30 percent in the past four years, data showed Monday.

According to a report by Incheon International Airport Corp., which was submitted to Rep. Lee No-keun of the ruling Saenuri Party, the airport gained 777 billion won ($645 million) from commercial facility rent fees last year, a 29.8 percent increase compared to that in 2010.

The area with the highest-priced rent was a duty-free shop run by Hotel Shilla at a cost of 154.6 billion won a year.

This was followed by Hotel Lotte’s duty-free shop (124.7 billion won), Lotte DF Global duty-free shop (95 billion won), and other smaller duty-free shops by Hotel Shilla (93.1 billion) and Hotel Lotte (87.7 billion), respectively.

Experts pointed out that rising rent prices contribute to overpriced airport products, as stores have to raise the prices of their products and services to keep up with the rent.