на протяжении уже Х лет

16:31 Oct 29, 2019 

As long as 25 can be 1, 2, 3, .....25.

15:13 Oct 28, 2019 

The proposed variants have the nuance of "up to 25 years," meaning that it could have been fewer years too.

13:50 Oct 28, 2019 

Если правильно понял ваш вопрос, Вы хотите узнать for as many as 25 years или for as much as 25 years?
Коллеги тоже предложили свои варианты, но мне кажеться вы хотите узнать разницу или какой из них лучше или правильно?
Да?
Если так, можете им сказать что оба правильные. Только есть разница! As many as 25 years-here the number of years highlighted.
as much as 25 years- here the amount highlighted. in your example, He may have lived in the United States for as much as 25 years - not the number, but "lived" as much-highlighted. The first used as countable, the second used as uncountable.

12:55 Oct 28, 2019 

+1

Let him thank zverovodov for 25 years of hard work. Plain and simple.

10:02 Oct 28, 2019 

the question is very clear, and a few people responded with very useful feedback.
I see your point, but I don't see any practical reason for your passionate intervention.

08:48 Oct 28, 2019 

because you do not need either. What a native would say is that the Big Kahuna thanked those good folks for the work they have/had been doing for (over) 25 years. That's it. What you are trying to do instead here is literally squeeze that Russian "vot uzhe" into the picture but it only makes your sentence stilted and unidiomatic. I said it a million times before and I will say it again: it never pays to just translate words.