Kharas defines the middle class as people who have enough money to cover basic needs, such as food, clothing and shelter, and still have enough for a few luxuries, such as luxury food, a television, a motorcycle, improvements to the house or higher Education.
It is a critical moment: after thousands of years of living most people on the planet as serfs, as slaves or in other destitute scenarios, half of the population now has the financial means 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 only royalty's and farmers, now we are about to have a majority middle-class world."
Today, the middle class has around 3.7 billion people, says Kharas, or 48 percent of the world's population. An extra 190 million (2.5 percent) consists of the mega-rich. Together, the two groups form a majority of humanity in 2018, a shift with far-reaching consequences for the world economy – and potential consequences for the happiness of millions of people.
1. How much does it cost to meet the Kharas & # 39; definition of bourgeoisie?
It depends on where you live and, more precisely, how expensive the things are where you live. The definition of Kharas takes into account the higher costs of meeting basic needs in places such as the United States, Western Europe and Japan than in a large part of developing countries.
In terms of dollars, Kharas defines the global middle class as those earning $ 11 to $ 110 per day, or about $ 4,000 to $ 40,000 per year. These are personal numbers, so families with two parents and several children need a lot more. It is a wide range, but remember that he adjusts the amounts per country to take into account how many people can buy with the money they earn. For example, earning $ 12,000 for a family of four in Indonesia would qualify for the global middle class, but that would not be in the United States.
2. What about the American middle class?
The median household income in the United States is just over $ 59,000. That is exactly in the middle of the United States, but according to Kharas' research, it is one of the 91st percentiles worldwide for a family of three, putting the American family at the top of the global middle class.
"Americans find it difficult to realize that the American middle class, in a global perspective, is pretty high," said Anna Rosling Rönnlund, who founded the Dollar Street project to photograph families and their lifestyles around the world.
3. Where do these new residents of the middle class come from?
Kharas estimates that every year 140 million to 170 million people move to the middle class. (More exact estimates are difficult to obtain, not all countries keep uniform records and in some places the data is years old.)
India and China have made much of the advance of the middle class in recent years. Now, Kharas said, Southeast Asian countries like Thailand and Vietnam are ready for a wave of the middle class.
4. So what does it look like and feel to be part of the global middle class all over the world?
Dollar Street, the project of the Swedish non-profit organization Gapminder, has photographed the daily lives of more than 250 families around the world. Their subjects include a family of five in Burundi, living on $ 324 a year and a family of five in China that makes $ 121,176 per year. The photos show the people and their homes, eating utensils, toilets, toothbrushes and transport, allowing people to compare lifestyles around the world.
Dollar Street recently photographed Angga and Yuli Yanvar, a couple in the early years & # 39; 30 with two young children, part of the emerging middle class in Indonesia. Angga is a social worker and Yuli is a teacher. The family has a refrigerator, electricity and an engine to be around, and their children have different toys, including bicycles and a battery-powered minicar. They save money to buy a house and car, goals that seem realistic in view of the fact that they earn slightly more than $ 12,000 a year in revenue.
What immediately jumps through the photo 's on Dollar Street is how remarkably the same daily life is around the world, with the exception of the very rich and poor. The vast majority of households have electricity, water in the house, children who go to school and some sort of transport.
"The most striking thing is that so many people we've visited so far actually have a plastic toothbrush," said Rönnlund, who started Dollar Street in 2015. "It's the same with soap, almost everyone in the world has access to some kind of toothbrush, the poorest buy a small part of a soap bar or make it yourself." When you come to the center, you see people locally-produced, large pieces of soap The higher your income scale, the better the soap becomes – or even multiple cleaning products. "
That ties in with Kharas's research. "These people in the global middle class have many things in common," he said. "They like air conditioning, a refrigerator, a car or a motorcycle to move around, and they enjoy going on holiday and do not have to work every day."
5. Does more money and more things make us happier?
There are endless discussions about how much money and which lifestyle would maximize happiness. The consensus among researchers who have studied this extensively is that the daily mood does not improve much after about $ 75,000 per year in the United States. There is not much noticeable improvement in mood afterwards, even when houses and bank accounts grow. That said, people also feel better when they go up the income ladder, do not go down or get stuck, which helps explain why the middle class in the United States and a large part of Europe is upset after years of stagnating income.
Ronnlund and her team have witnessed some of these trends with the Dollar Street project. They do not specifically ask for happiness, but they have asked every family they photographed about their favorite things they own and what they would like to buy if they had a little more money.
A poor family picked up a plastic bucket as their favorite possession because it was the difference between life and death for them. They dreamed of getting a phone or a better bike. Families from the middle class valued things that made their lives better, such as air conditioning or a fridge, and they wanted to own cars or houses. Richer families appreciated items such as special alcohol, exotic plants or beautiful stuffed unicorns.
"I thought it would be easiest to photograph rich people, but it was the opposite," Rönnlund said. "Richer people find it harder to make people come home as they are, they want to present it in the right way so that they look good and present the social media version of themselves."
This article was written by Heather Long and Leslie Shapiro, reporters from The Washington Post.