I think about 30% of the words in an English text are loan words, and I would guess that's quite a high proportion compared to other modern European languages, but not particularly amazing.

The definition of loan word is a bit vague, of course, and the origin of some words is uncertain, and the proportion of loan words will depend a bit on the topic and the style of writing.

(There are 72 words in the previous two paragraphs, if you expand "30%" and "that's". So about 22 of them should be loan words? Seems plausible ...)