Call schedules vary greatly from program to program and there doesn't seem to be a real pattern in terms of how many residents they take. Call at most places will be Q4-6 at least through your PGY-3 level (very few if any that I interviewed at were Q3 unless someone was on vacation). Some programs with unique call schedules were Mayo, Barrow and UT-Memphis to name a few, but they are all bigger programs.
Some programs list their call schedule on Frieda but it is often inaccurate.