Last year I had archived 2,270 emails to and from (and about) students. (I make a separate folder for each student and file everything related to that student.) The breakdown from the data last year was here.
This year, the total comes to 3,364 emails. The reason for the increase is probably due to the reassessments in calculus… students had to send me an email justifying their request for a reassessment.
The student with whom I had the least communication to/from/about had 16 emails. The student with the most had 192 emails. Each student on average has 71 emails.