Let's do some napkin math: Iran has about 94 million people. Iran's IRGC alone has a personnel count of 125.000 [1], of which about 2-5000 are estimated to be the elite of the elite ("Quds Force"). Together with the Basij (anywhere from 100-600k) that alone is a sufficient amount of force. And on top of that come maybe 400-500k of the regular Iranian Armed Forces [2], as well as about 260k active police+100k police reservists.

So, if one sees the whole of IRGC plus Basij as the "commandos", they alone form an active elite of about 0.5%, if one sees the entirety of the military+police we're looking at easily 2-3 million units, so up to 2%.

[1] https://en.wikipedia.org/wiki/Islamic_Revolutionary_Guard_Co...

[2] https://en.wikipedia.org/wiki/Islamic_Republic_of_Iran_Armed...