Not much fewer, but some. But I am not sure if the reason was cooperative learning or the time it takes for students to develop their understanding. If cooperative learning is used extensively, less topics are covered. Different topics were covered. I do feel that we were able to more richly address those topics that were included however, and this helped in some of the later sections in the book that return to some of the strands we started earlier in the course.
Answer depends a lot on the course.
Where a rigid syllabus is required, I ask students to do more reading outside of class. Or I prioritize, covering some topics in less depth. Sometimes I feel that I have not covered enough. Fewer, you leave out topics you believe are not as useful as the ones you cover. I get more material covered than ever before.