Who Invented Country Phone Codes and Why?

Ever wondered what country phone codes actually mean? And why are there only two single-digit codes in the world, while all the others have two or even three digits? Look, only four countries have a golden code: plus one for the USA and Canada, and plus seven for Russia and Kazakhstan. However, Kazakhstan uses plus seven temporarily. So where's plus two, plus three, and all the rest? The thing is, in the '60s, the world was divided into phone regions, and each region was assigned its own starting number. Plus one went to North America, plus two to Africa, plus three and plus four to Europe, plus five to Central and South America, plus six to Southeast Asia and Australia, plus seven to the USSR, plus eight to East Asia, and plus nine to the Middle East. So single-digit codes were given to the top priority countries for quick communication, while others were first assigned a regional code and then a unique number for each country. And you know what doesn't exist? A plus zero code. Maybe they're saving it for Antarctica, or even the Moon.