21. Personnel Expenses
The personnel expenses mentioned in notes 19 and 20 above are as follows:
  | 
            
  | 
            Year Ended December 31,  | 
        ||||
(in thousands of $)  | 
            
  | 
            2022  | 
            
  | 
            2021  | 
            
  | 
            2020  | 
        
Short term employee benefits – Salaries  | 
            
  | 
            216,847  | 
            
  | 
            135,676  | 
            
  | 
            75,437  | 
        
Short term employee benefits – Social Security  | 
            
  | 
            16,274  | 
            
  | 
            12,785  | 
            
  | 
            9,087  | 
        
Post-employment benefits  | 
            
  | 
            5,406  | 
            
  | 
            2,864  | 
            
  | 
            1,242  | 
        
Termination benefits  | 
            
  | 
            401  | 
            
  | 
            818  | 
            
  | 
            1,005  | 
        
Share based payment  | 
            
  | 
            151,912  | 
            
  | 
            167,965  | 
            
  | 
            92,558  | 
        
Employer social security contributions stock options  | 
            
  | 
            5,910  | 
            
  | 
            5,002  | 
            
  | 
            15,214  | 
        
Total personnel expenses  | 
            
  | 
            396,750  | 
            
  | 
            325,110  | 
            
  | 
            194,543  | 
        
The post employment benefits relate to the pension plans the Company has in place for its employees.
The average number of full-time equivalents (FTE) employees by function is presented below:
  | 
            
  | 
            Year Ended December 31,  | 
        ||||
(Average Number of FTE)  | 
            
  | 
            2022  | 
            
  | 
            2021  | 
            
  | 
            2020  | 
        
Research and development  | 
            
  | 
            474.8  | 
            
  | 
            349.7  | 
            
  | 
            213.0  | 
        
Selling, general and administrative  | 
            
  | 
            442.4  | 
            
  | 
            264.4  | 
            
  | 
            119.5  | 
        
  | 
            
  | 
            917.2  | 
            
  | 
            614.1  | 
            
  | 
            332.5  |