I've searched the internet and can't find any more recent data than 2004 when a survey revealed that pulic sector absenteeism was costing the economy over £4 billion a year.
The fact that no figures have been published since suggests to me that the problem is even worse now.
It has to stop – we can't afford to have people off sick for 6 months on full pay and then miraculously "recover" just befor the 6 months are about to end.
Public sector absenteeism is consistently higher than that in the private sector. All the "back to work" interviews in the world won't have any material effect. Hit people in the pocket and watch how healthy they suddenly become!