as alluded to in the previous replies, it's not just the total number the er sees. it really depends on if you get to see it. for instance, if an er has only 20,000 visits a year but there is usually only one resident on at a time, then likely you will get to do the procedure, see the sick patient, etc...
i realize that the higher the number of visits, the higher the chances of you seeing diverse/sick pathology. but also, the larger pure numbers of bs/fast track stuff. just pure stats.
asking to see resident logs is an idea but a lot of programs don't strictly enforce procedure logs. it's hard to take time to keep track once you;ve gotten a lot of a certain procedure.