Approximate values of amount modifiers [duplicate]

This is an area of English that I consistently have trouble with. Consider the following sentences.

1. I have a couple of books on my desk.
2. I have a bunch of books on my desk.
3. I have a number of books on my desk.
4. I have a few books on my desk.
5. I have several books on my desk.
6. I have many books on my desk.

How many books, give or take, do I have on my desk in each case?

[digression: one example of how I tend to get these wrong is the following: not long ago, my wife (native speaker of American English) and me were out with a few friends from out of town. At one point I said "[famous landmark] is only two hundred meters from here", to which my wife replied "no, it's more like a a couple hundred meters".]

1. I have a couple of books on my desk.

   2, no arguments. A couple is 2. NB: If the person saying it is a couple is wrong (maybe distance), it is unlikely to be more than 4 or 5 of that item / unit. Kudos @Bye

   two people or things of the same sort considered together.
   -- Google Dictionary

2. I have a bunch of books on my desk.

   Same as a number - undefined:

   a number of things, typically of the same kind, growing or fastened together.
   -- Google Dictionary

3. I have a number of books on my desk.

   Not defined, anywhere from 1 to 1000000...

   a quantity or amount
   -- Google Dictionary

4. I have a few books on my desk.

   I go for 3 or 4

   a small number of.
   -- Google Dictionary.

5. I have several books on my desk.

   Same as above in my opinion - 3 or 4

   more than two but not many.
   -- Google Dictionary

6. I have many books on my desk.

   A lot, more than 10 I would say - but it depends on what you are referring - I have many pets could be 5+, there are many stars in the sky is 1,000,000,000+

   a large number of.
   -- Google Dictionary.