Chinanews, Beijing, June 13 - "Chinese urbanites earn a gray income, or the income without a clear source, of 4.4 trillion yuan every year," said Wang Xiaolu, deputy director of National Economic Research Institute (NERI) of China Reform Foundation, on June 8 in Beijing.According to Wang, the data were collected from 2,000-plus friends, relatives or other acquaintances of researchers in NERI, but not from general survey, which are mostly used by the National Statistics Bureau, and should be trusted. The data are based on their expenditure, especially expenditure on cars, houses, overseas travel, as well as their family deposit.NERI's research shows that urbanites with highest income (taking up 10% of urban population) earned an average annual disposable income of 97,000 yuan in 2005, while the figure in the report of National Statistics Bureau was only 29,000 yuan. It is common for many high-income persons to have a gray income.NERI estimates that the total annual income of Chinese should be 12.7 trillion yuan, rather than the 8.3 trillion yuan as given by National Statistics Bureau. The families with highest income earns an income of nearly 55 times of the income of the families with lowest income, while previous data says the income gap is only 20 times between the two.