How big is the income gap among the middle class in Asia? The data will surprise you.

Vietnam starts at $6,000-18,000 per year, India at 6 million rupees (about $7,000) is considered comfortable, while China's first and second-tier cities jump directly to $28,000-85,000.

The most surprising thing is that the middle class in Japan, a developed country, is shrinking, with more and more people falling into "working poverty." In contrast, the middle class in India, Indonesia, and the Philippines is rapidly expanding, with India expected to reach 800 million middle-class individuals by 2030.

In simple terms: the middle class in developed countries is being squeezed, while the middle class in emerging markets is exploding. This is also why the engine of global consumption growth is in Asia now.