If I was to follow my subjectivity, then for me it is Franco Makiadi and Burning Spear (probably you have never heard of them - you shouldnÂt care either, they have not sold a million copy!
However, if I was to be pragmatic and objective, then it would be Stevie Wonder. He has more than thirty top 10 hits, 22 Grammy Awards, which is the most for a solo artist. If Stevie had only one hit song out of the several you already know, he would have been just as famous as he is today! That is genius