who coined the phrase less developed country?

Question

basically, I want to know the approximate year and source of who began the use of Developed Countries (DCs) and Under Developed Countries (UDCs) or Less Developed/Developing Countries (LDCs). Thanks.

Answer 1

In the UN annual report 1971 (got it in the French wiki-page) and this seems logical to me. UN usually coins these so sensitive words.

Answer 2

It happened somewhere after the telephone, so @ 1900

and one person is not responsible for it.