Population below $1 a day is the percentage of the population living on less than $1.08 a day at 1993 international prices. As a result of revisions in PPP exchange rates, poverty rates cannot be compared with poverty rates reported previously for individual countries. Data showing as 2.0 signifies a poverty rate of less than 2.0 percent. Nationally representative primary household surveys conducted by national statistical offices or by private agencies under the supervision of government or international agencies and obtained from government statistical offices and World Bank Group country departments.
UNDPのHuman Development Report 2007/2008でも80%でした。ただし、1990-2005のどこかでのデータなので、かなり古いかもしれません。