After readning Srin san's reply, I reread this thread again.
Yeah, even in Japanese we have many vague expressions.
I searched about "not a few" and "quite a few" at Space Alc.
THey say "not a few" means "ツ渉ュ窶堙遺?堋ゥ窶堙ァ窶堙環、窶堋ゥ窶堙遺?堙ィ窶堙個絶?昶?堙個、窶佛?窶懌?督絶?昶?堙? and give an example "not a few countries in the world"ツ(ツ青「ナ?E窶吮??窶堙個渉ュ窶堙遺?堋ゥ窶堙ァ窶堋エ窶堙ゥツ坂?伉々ツ).
Hmm, when I hear the word "ツ渉ュ窶堙遺?堋ゥ窶堙ァ窶堋エ窶堙ゥ", I won't think it meant 窶堋ゥ窶堙遺?堙ィ窶堙個絶? or 窶堋ス窶堋ュ窶堋ウ窶堙ア窶堙?,,.
Maybe when I hear the expression ツ青「ナ?E窶吮??窶堙娯?堋ス窶堋ュ窶堋ウ窶堙ア窶堙個坂?伉々ツ、I'll imagine more countruies than ツ青「ナ?E窶吮??窶堙個渉ュ窶堙遺?堋ゥ窶堙ァ窶堋エ窶堙ゥツ坂?伉々.
At the same time, I feel 窶堋ス窶堋ュ窶堋ウ窶堙ア窶堙個坂?伉々ツ is a neutral expression and ツ渉ュ窶堙遺?堋ゥ窶堙ァ窶堋エ窶堙ゥツ坂?伉々 implies something that the writer wants to say....like the number of those countries is supposed to be small but there are more countries than supposed.
Anyway don't you think many kinds of expressions make the sentence rich?
ツ(Hmmm I want to say 窶堙??堙俄?堋ゥ窶堋ュツ、窶堋「窶堙ォ窶堋「窶堙ォ窶堙遺?「\ナ陳サ窶「テサ窶邸窶堋ェ窶「ツカ窶堙ー窶鏑窶堋ゥ窶堙俄?堋キ窶堙ゥ窶堙?スv窶堋「窶堙懌?堋ケ窶堙ア窶堋ゥツ?ツ)
This is just my feeling and I hope my post makes sense.....
Please ignore my post if you are confused.
I rewrite my post because I don't think I should have used 窶ーツシ窶凖ィ窶邸 in this sentence.