Ad spend continued to slump in November, says SMI
The 2018 second-half ad slump continued in November with a 4.4% fall in agency bookings, compared to the same month in 2017, however Standard Media Index is confident the year is on track to record the highest ever ad spend overall.
October’s collapse, which saw all sectors fall and 10.2% drop in overall spend, wasn’t repeated on the same scale, with the radio, outdoor and cinema channels all reporting growth during November.

Wouldn’t have anything to do with the data being weekly and therefore some months have five weeks and some have four weeks?