CHINA'S fledgling advertising industry is growing rapidly, with more than 20,000 firms in business nationwide producing a combined turnover of 4.27 billion yuan (about HK$5.55 billion) in the past six months, a report has revealed. The turnover figure was 51.3 per cent up on the corresponding period last year. Shanghai accounted for 800 million yuan, Beijing 600 million yuan , and Guangzhou 500 million yuan, said Xinhua (New China News Agency).