Families which made their money in the real estate industry saw their wealth shrink by more than 80 percent annually so far this year because the Chinese government imposed several measures to curb speculation in the property market, according to a survey on Sunday.

The combined family wealth of 592 individuals in the industry dropped to 445.7 billion yuan (US$69 billion) this year, a sharp fall from last year's 2.24 trillion yuan, a Shanghai-based business magazine, Money Weekly, said in the survey.

"From this list of rich families in the Chinese mainland, we can detect an apparent drop of the weighting from real estate," the magazine said. "Compared with other fast-growing sectors like biotechnology, information technology or new energy, realty seems to be losing out."

The magazine's survey listed 23,179 rich families on the Chinese mainland. The family of Liang Wengen, chairman and main shareholder of the Sany Group, China's largest construction equipment manufacturer based in Hunan Province, ranked at the top of the list with wealth of 59.8 billion yuan. Liang was China's second-richest person with an individual wealth of US$8 billion, according to Forbes' survey in March.

Robin Li, head of China's biggest online search engine Baidu Corp, was ranked second in the Money Weekly's survey with family assets of 53.6 billion yuan.

China has launched several curbs to restrict home purchases in big cities since April. The State Council, or Cabinet, said earlier this month the curbs imposed in big cities now would extend to second- and third-tier cities.