The International Food Policy Institute reports,

the ultra poor are overwhelmingly concentrated in one region—Sub-Saharan Africa is home to more than three-quarters of the world’s ultra poor. Sub-Saharan Africa is also the only region in the world in which there are more ultra poor than medial or subjacent poor. In contrast, most of Asia’s poor live just below the dollar-a-day line; only a small minority of the population is ultra poor.

What they have done is sub-divide those living on less than $1 a day into those earning $.75 to $1 (the subadjacent poor), those earning from $.50 to $.75 (the medial poor) and those living on less than $.50 a day (the ultra poor).

One take-away from the report is that the relatively encouraging reduction in world poverty that has taken place in the past 15 years may not continue.