17. Trade and other receivables

17. TRADE AND OTHER RECEIVABLES
 
EUR million Note 31 Dec 2016 31 Dec 2015
Trade receivables   282.4 255.4
Prepaid expenses and accrued income      
Unbilled earned net sales   53.9 41.9
Licence fees   21.1 19.8
Rents   2.8 3.2
Social costs   3.1 2.1
Accrued interest income   0.0 0.4
Receivables on stock options   - 0.0
Other prepaid expenses   19.2 20.7
Derivate receivables 26 2.4 1.6
Other   5.4 8.8
    390.3 353.9
 
Aging and provision for doubtful trade receivables
 
EUR million   31 Dec 2016 31 Dec 2015
Not past due   236.0 223.9
Past due 1–30 days   41.6 26.7
Past due 31–60 days   3.3 3.9
Past due 61–90 days   0.9 0.9
Past due 91–180 days   0.6 0.3
Past due 180+ days   1.5 0.5
Provision for doubtful receivables   -1.5 -0.8
    282.4 255.4
       
Provision for doubtful receivables, of which      
Past due less 91 days   - -0.1
Past due 91–180 days   -0.6 -0.2
Past due 181+ days   -0.9 -0.5
    -1.5 -0.8