According to the report, the structure of Chinese shoppers will largely change. The new mainstream group is expected to occupy 51 percent of all households by 2020, up from 14 percent now. Meanwhile, the upper mass group, which makes up 54 percent now, will shrink to 25 percent in 2020.
New mainstream customers are defined not only by their income but also by a new way of living and spending, Magni added.
China will gain itself a position among "upper-middle income" economies by World Bank standards by 2020, an economics expert predicted on Oct 9.
China's annual per capita GDP is likely to top $10,000 by 2020 from last year's $5,530, Cai Zhizhou, an economics professor at Peking University, was quoted as saying in a report in the 21st Century Business Herald.
By then, China will fall into the income range of upper-middle income economies set by the World Bank, he said.
According to a recent report by The Economist, there are more than 1 million Chinese people whose individual assets exceed 10 million yuan ($1.6 million).
However, Chinese people's confidence about their future income is declining.
Although still among the world's most optimistic concerning their economy, the Chinese expressed a dimmer view with regard to rises in their personal income, the McKinsey & Co report found.
At least 56 percent of respondents agreed that they expect their household income to significantly increase over the next five years, down from 60 percent a year ago. The percentage of optimists climbed to a peak in 2010 with 62 percent but declined over the next two years.