The word(s) "why" appears 77 time(s) in 72 verse(s) in Quran in Abdullah Yusuf Ali translation.

(51) If (We had) not (sent thee to the Quraish),- in case a calamity should seize them for (the deeds) that their hands have sent forth, they might say: "Our Lord! why didst Thou not sent us a messenger? We should then have followed Thy Signs and been amongst those who believe!"

(52) But (now), when the Truth has come to them from Ourselves, they say, "why are not (Signs) sent to him, like those which were sent to Moses?" Do they not then reject (the Signs) which were formerly sent to Moses? They say: "Two kinds of sorcery, each assisting the other!" And they say: "For us, we reject all (such things)!"

(53) Ye they say: "why are not Signs sent down to him from his Lord?" Say: "The signs are indeed with Allah: and I am indeed a clear Warner."

(54) They will say to their skins: "why bear ye witness against us?" They will say: "Allah hath given us speech,- (He) Who giveth speech to everything: He created you for the first time, and unto Him were ye to return.

(55) Had We sent this as a Qur'an (in the language) other than Arabic, they would have said: "why are not its verses explained in detail? What! (a Book) not in Arabic and (a Messenger an Arab?" Say: "It is a Guide and a Healing to those who believe; and for those who believe not, there is a deafness in their ears, and it is blindness in their (eyes): They are (as it were) being called from a place far distant!"

(56) Also, they say: "why is not this Qur'an sent down to some leading man in either of the two (chief) cities?"

(57) "Then why are not gold bracelets bestowed on him, or (why) come (not) with him angels accompanying him in procession?"

(58) why then was no help forthcoming to them from those whom they worshipped as gods, besides Allah, as a means of access (to Allah)? Nay, they left them in the lurch: but that was their falsehood and their invention.

(59) Those who believe say, "why is not a sura sent down (for us)?" But when a sura of basic or categorical meaning is revealed, and fighting is mentioned therein, thou wilt see those in whose hearts is a disease looking at thee with a look of one in swoon at the approach of death. But more fitting for them-

(60) It is We Who have created you: why will ye not witness the Truth?