elcento

Here the seam is genuine, and that is the point of the page.Procento at rank 1995 looks as though it is built from po and cento and is not: it is one borrowed root, and its page explains the trap in full. Elcento is the opposite case. It really is el plus cento, a hundred, and you really can take it apart: so many out of a hundred.

There are three words for this and Esperanto has kept all of them.

• Procento is the international borrowing and the one you will meet most. It is also by a wide margin the commonest of the three in this course's own frequency corpus.
• Elcento is the home-built one. Reta Vortaro's note says it leans on the separating out of the share from the whole, which is why it reads naturally in el la lernantoj nur malgranda elcento finas la studadon.
• Pocento is the third, built on po, the preposition meaning at the rate of. The same note says it leans on the repetition of the figure, as in du pocentoj de la loĝantaro.

What to actually do. Write procento and you will never be wrong or misunderstood. Reach for elcento when the sentence is about a slice taken out of a total, which is most of the time when you are writing about statistics in prose rather than quoting a figure. Recognise pocento when you meet it and do not treat it as a mistake. All three take da or de for the whole they are part of, all three pluralise normally, and the symbol % is read aloud as whichever of them you prefer.