In the whole world, there are more farmers than any other profession. Farming is the biggest sector in all continents except Europe and North America.
The most common profession is Politician; as that is now considered its own profession - ignoring that, the most common non-political profession is Lawyer / Attorney.
Lawyer
By far the most common profession was the military. A poor man could enlist and upon retirement have either land or a cash bonus plus his savings that he accumulated over the years. Another common profession would have to be the "world's oldest profession", for both men and women.
They are rich that is for sure.
Lawyer and Military
Speaking in Japanese
Law is the most common profession among the US presidents.
nose
teacher
The most common profession of Congressman is the law.
More US presidents were lawyers before they became President. 25 of the 43 presidents were admitted to the bar, although not all them earned their living that way.Of course, if you consider politician to be a profession, even more of them engaged in that.
The most common previous job of members of Congress is a lawyer. There are also numerous businessmen, public servants and educators.