TAIPEI, May 9 (Xinhua) -- The net profits of listed manufacturing companies in Taiwan grew 13.4 percent year on year in 2017, posting the biggest increase in three years, the island's economic authority said in a report.

Their net profits reached 1.5 trillion new Taiwan dollars (about 50.8 billion U.S. dollars) and left an overall after-tax profit margin of 9.1 percent, according to the report on Tuesday.

The count covered all companies listed on the Taiwan Stock Exchange and the secondary bond market of the Taipei Exchange.

Among all the industries, electronic components companies contributed the largest share of net profits, about 652 billion new Taiwan dollars.

Taiwan Semiconductor Manufacturing Company Limited (TSMC) made a net profit of 341.1 billion new Taiwan dollars, followed by Foxconn Technology Group's 138.7 billion.

In terms of research and development (R&D) input, TSMC also played a leading role by spending 79.9 billion new Taiwan dollars, nearly 20 percent of the entire of the manufacturing sector.