Total sales for South Korean companies dropped for two straight years in 2015 from a year earlier amid a protracted economic slump and low oil prices, government data showed Tuesday.

The combined sales from 12,181 companies, excluding financial firms, reached 2.16 trillion won ($1.84 billion) last year, down 3.2 percent from a year earlier, according to the data compiled by Statistics Korea. It is based on a survey of 12,460 companies with more than 50 regular workers and a paid-in capital of more than 300 million won.

It marked the second consecutive on-year drop since 2014 when it posted a minus figure for the first time.

However, their net pretax profit rose 16 percent to 108.8 billion won last year.

"A sharp drop in oil prices dragged down sales of the country's businesses, especially those in the manufacturing sector, but it pushed up their net profit on reduced costs," said the agency.

The number of manufacturing firms totaled 5,817 in South Korea, accounting for 46.7 percent of the total surveyed companies.

The aggregated employment by the companies was 4.38 million last year, with 3.84 million, or 87.7 percent, being full-time workers.

Their combined outlays in research and development (R&D) reached 39.2 trillion won in 2015, down 10.1 percent on-year, as businesses remain reluctant to set aside money on R&D projects due to economic uncertainties in the future, the statistics office said. (Yonhap)