A. "about 22% of the world population" is not correct.

Those among the poorest 22% of the world's population are incredibly poor by U.S. standards. They are the 1.3 billion people who, according to new World Bank data, have incomes below what the Bank designates as the absolute poverty line: $1.25 per day — or roughly $450 per year. There are just no such poor people in the United States.

Although U.S. poverty thresholds are differentiated by gender, age, place of residence and other criteria, the average poverty line for a "typical" household of four is $22,400 annually. This works out as a little over $15 per day per person — or twelve times higher than the World Bank's absolute poverty line.

B. "about half of the world population" is not correct.

People exactly in the middle of the global income distribution have incomes of less than $1,500 a year per person (adjusted for purchasing power), or just a bit over $4 per day. This is close to the average level of income in countries like Cambodia and the Philippines. Again, there are no such poor people in the United States or in the rest of the rich world.

C. "about 65% of the world population" is correct.

People who are around 65th percentile by income make about $2,800 a year per person (also adjusted for purchasing power). This is the average income level of people in Thailand. There are indeed some among the very poor in the United States whose incomes are around that level. They are considered "extra poor" by U.S. standards.

D. "about 80% of the world population" is correct.

The income of those who are just sufficiently "bad off" to be considered poor in the United States is about $5,600 a year per person (or $22,400 for a four-person household). This is slightly less than the average income in Poland, and it makes these Americans better-off than about 80% of the world population, according to economist Branko Milanovic, author of a recent book on global income distribution, The Haves and the Have-Nots.

The poorest Americans benefit from a social safety net that the vast majority of the world's poor must do without. On the other hand, there are in-kind goods and services that are consumed by the people in poor countries that may not always be fully reflected in the household surveys from which income data is derived. The two biases might balance themselves out.