Almost half the world's population -- 3.4 billion people -- live on less than $5.50 a day, the World Bank reported Wednesday. That's about the cost of a Starbucks Venti Caffe Latte in New York City.

About a quarter of the planet's people, or around 1.9 billion, make do on less than $3.20 a day, and 10 percent scrape by on less than $1.90 a day, according to the World Bank's biennial Poverty and Shared Prosperity Report.

The World Bank said its $3.20 a day figure reflects the typical poverty line in what it calls lower-middle-income countries and the $5.50 a day number reflects the poverty line in upper-middle income countries. Among developing regions, Europe and Central Asia had the lowest percentage of people living under the $3.20 and $5.50 poverty lines.

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Extreme poverty, defined as living on less than $1.90 a day, fell from 36 percent of the world's population back in 1990 to 10 percent in 2015, the most recent year for available data. But the pace that extreme poverty is being reduced has slowed in recent years, the World Bank warned last month.

Incomes of the poorest people grew in 70 of the 91 economies monitored, with their incomes rising faster than average in more than half of the 70 economies, according to the report.

In the East Asia and the Pacific region, incomes of the poorest 40 percent grew 4.7 percent on average between 2010 and 2015. "While extreme poverty is very low, the region saw a higher percentage of people lacking access to sanitation," the report found.

One third of the countries in Sub-Saharan Africa saw incomes decline for the bottom 40 percent of their populations, with the region home to the largest number of extreme poor.

"Africa saw its population nearly double between 1990 and 2015, with one of the largest increases in population being for those living on less than $3.20 and more than $1.90 {per day]. The poor suffered from multiple deprivations such as low consumption levels and lack of access to education and basic infrastructure services," the bank said.

Progress in sharing prosperity lags in some regions, with data difficult to come by in the countries where improvements are most needed, the report warned.

Another 3.8 billion people around the world live in homes with enough discretionary income to be viewed as "middle class" or even "rich," according to other findings recently released by the Brookings Institution, a left-leaning think tank.