The data is not 100% foolproof, especially for digital spend, but it does provide a bellwether for how each of the media agencies and their networks did in the previous year's trading.
This year's table, covering the 2008 calendar year, demonstrates further consolidation of UK media billings into the top four marketing services agency networks - WPP, Omnicom, Publicis and Aegis - but very different fortunes for the respective groups.
WPP demonstrated its might yet again, with all four of its agencies increasing their billings in 2008 - MediaCom by 4.11% to officially break the £1bn billings barrier for the first time, Mindshare by 0.03%, Mediaedge:cia by 4.92% and Maxus (formerly BJK&E) by 10.41%.
Aegis also performed more than creditably, with Carat up 6.47%, Vizeum up 13.21% and Feather Brooksbank holding steady, down just 0.76%.
But the results were much less positive for Publicis, Omnicom and Interpublic. Billings were down 15.5% at Publicis' Starcom UK Group, 15.03% at ZenithOptimedia and 13.31% at Zed Media.
Billings at Omnicom's OMD, which includes Manning Gottlieb OMD, were down 10.34%, and PHD was down 13.78%.
At IPG, the bad news continues, with Initiative billings down 21.62% and Universal McCann falling 17.27%.
In today's economic climate, the trend for the strong to grow stronger will only continue, with clients increasingly looking to consolidate their media accounts with one global agency network, as HP, Fiat, Renault-Nissan and Santander have all done to some extent in recent months. There is also a smaller trend for choosing media agencies in the same marketing services group as clients' creative agencies.
There is still room to manoeuvre, however, and an independent such as Walker Media has maintained its place in the top 10 agency list with its line-by-line trading offer. But the evidence suggests Phil Georgiadis' agency is bucking the trend rather than providing a template that will shape the future.
Billings aren't everything, but over at WPP Towers, Sir Martin Sorrell will look at these figures with some satisfaction and conclude that his media agency strategy is working extremely well, thank you very much.
Steve Barrett is editor of Media Week, firstname.lastname@example.org