The world is on the brink of a historic milestone: By 2020, more than half of the world’s population will be “middle class,” according to Brookings Institution scholar Homi Kharas.

Kharas defines the middle class as people who have enough money to cover basics needs, such as food, clothing and shelter, and still have enough left over for a few luxuries, such as fancy food, a television, a motorbike, home improvements or higher education.

It’s a critical juncture: After thousands of years of most people on the planet living as serfs, as slaves or in other destitute scenarios, half the population now has the financial means to be able to do more than just try to survive.

“There was almost no middle class before the Industrial Revolution began in the 1830s,” Kharas said. “It was just royalty and peasants. Now we are about to have a majority middle-class world.”

Today, the middle class totals about 3.7 billion people, Kharas says, or 48 percent of the world’s population. An additional 190 million (2.5 percent) comprise the mega-rich. Together, the two groups make up a majority of humanity in 2018, a shift with wide-reaching consequences for the global economy — and potential implications for the happiness of millions of people.

Mentions Dollar Street, with its Toothbrushes of the World collection, filtered by income.

Also answers the "Does more money and more stuff make us happier?" question in the negative, rather brazenly linking to a Vox article that painstakingly 'splains how everyone interprets the study wrong; plenty of research suggests that life-satisfaction does increase with additional income, the ceiling applies to "day-to-day mood."

Brookings: The unprecedented expansion of the global middle class