I guess it depends. And I think that you'll find the highest (reading) speed during the plenary sittings in Strasbourg. You can just take a text randomly and do the maths by yourself:
For example, in this debate on the threat posed by chartering to flag state responsibilities under the CITES Convention, the speaker Gabriel Mato Adrover reads at 10:49 am in less than 5 minutes 810 words (here is the transcript of the text). That means that he reads at a speed of over 165 words per minute, which is, as you can imagine, way too fast. The normally agreed reading speed for a text for which interpretation is to be provided must not exceed 100 words per minute.
Unfortunately I don't think you will be able to find the average word-per-minute speed for all Spanish-speaking delegates at all EU institutions...