In my memory, during the peak summer period, around 17 / 18 rotations per week, so 36 - 38 sectors. In those days it wasn't unusual for an IT operators, such as BY or KG to depart ca. 07:00 on a route like BHX/PMI, returning around 13:30, out again at 14:30 on a similar duration trip, returning around 20:30, then an overnight rotation departing at around 21:30, returning in the early hours.
Obviously on longer runs, such as TFS, LPA or HER they may have only squeezed 2 trips per day (4 sectors) out of the aircraft.
These days it seams as though the ghastly overnight rotations have become less common.