A growing number of venture firms increased their annual revenue last year by expanding their businesses overseas, emerging as the new growth engine of the South Korean economy, a report showed Monday.

Among 69,801 venture firms in South Korea, 454 reported over 100 billion won ($97.6 million) in sales last year, up 9.1 percent from 2012, according to a report by the Small and Medium Business Administration.

The number steadily increased from 78 in 2005, 202 in 2008 and 381 in 2011, the SMBA said.

Fifty-six companies passed the sales threshold last year for the first time, including Nanos, a thin optical film maker, at 216 billion won; Kakao Talk, the mobile messenger service, at 210.8 billion won; and Haesung Optics, a lens and camera module manufacturer, at 182.8 billion. (Yonhap)