The World Bank has upgraded Bangladesh, Kenya, Myanmar, and Tajikistan to its lower middle income classification from least developed countries (LDCs) while South Sudan has fallen back into the low-income group.

In a statement released late on Thursday, the World Bank said Gross National Income per capita (GNI) was continuing to improve in these countries, allowing them to join the group where annual incomes range from $1,046 to $4,125.

Each year on July 1, the World Bank revises the income classification of the world's economies based on estimates of GNI per capita for the previous year.

The bank noted that over the past 24 years the per capita GNI of Malawi had risen by $70 while that of Norway had gone up by $77,040.

The new figures also showed that Argentina, Hungary, Seychelles, and Venezuela had moved from the upper middle-income category to high-income, with average per capita income levels now of $12,736 or more.

That is despite the fact that Argentina is in technical default on its external debt while Venezuela is in recession and at risk of default.

Bangladesh prime minister Sheikh Hasina on Thursday told a meeting that the country aimed to graduate to the middle-income category ahead of the targeted 2021 date.