Difference between ほとんどのX and Xのほとんど


I'm used to seeing ほとんどのX to mean 'most X'. Sometimes I see Xのほとんど like in
[this question](https://japanese.stackexchange.com/questions/52847/how-is-
this-%E3%81%BB%E3%81%A8%E3%82%93%E3%81%A9-used). Are both forms equally valid?
do they have exactly the same meaning? For example is there any difference
between the following:

> ほとんどの果物は丸い。  
>  果物のほとんどは丸い。  
>  Most fruits are round.

Edit: I'm failing to see how this is a duplicate of a question I already added
a link to. If I'm missing something please let me know.




It would indeed be tempting to say that these two constructions are
effectively one and the same, but there are some instances where you simply
cannot use them interchangeably. The subtle nuances are easier to grasp when
they are translated into English.

> [Grammatical]: **ほとんどの** 果物は丸い。
>
> = **Most** fruits are round. [adjective-ish]
>
> [Grammatical]: 果物 **のほとんど** は丸い。
>
> = Fruits are **almost always** / **in most cases** round. [adverb-ish]

* * *

With this in mind, let's take a look at the following example:

> [Grammatical]: ... その原因 **のほとんどは** 運転手のミスである。
>
> = They are **almost always** / **in most cases** caused by ... [adverb-ish]

In this specific instance though, you cannot switch the words around and use
the adjective-ish construction ほとんどのX:

> [NOT grammatical]: **ほとんどの** その原因は運転手のミスである。
>
> = **Most their** causes are ... [adjective-ish]

It is the word その [its/that/their] that makes this adjective-ish construction
impossible here.

Bear with me here, as I have intentionally used clumsy English phrasing "most
their causes are" for the sake of better capturing the feel of the Japanese
sentence.




It would indeed be tempting to say that these two constructions are
effectively one and the same, but there are some instances where you simply
cannot use them interchangeably. The subtle nuances are easier to grasp when
they are translated into English.

> [Grammatical]: **ほとんどの** 果物は丸い。
>
> = **Most** fruits are round. [adjective-ish]
>
> [Grammatical]: 果物 **のほとんど** は丸い。
>
> = Fruits are **almost always** / **in most cases** round. [adverb-ish]

* * *

With this in mind, let's take a look at the following example:

> [Grammatical]: ... その原因 **のほとんどは** 運転手のミスである。
>
> = They are **almost always** / **in most cases** caused by ... [adverb-ish]

In this specific instance though, you cannot switch the words around and use
the adjective-ish construction ほとんどのX:

> [NOT grammatical]: **ほとんどの** その原因は運転手のミスである。
>
> = **Most their** causes are ... [adjective-ish]

It is the word その [its/that/their] that makes this adjective-ish construction
impossible here.

Bear with me here, as I have intentionally used clumsy English phrasing "most
their causes are" for the sake of better capturing the feel of the Japanese
sentence.

