Original sentence: The GEO's headline figure was 23% (based on median hourly earnings of all employees) not the 12.8% (median hourly earnings of full-time employees only) used by the ONS
Edited sentence: The GEO's headline figure was 23%, which was based on median hourly earnings of all employees, not the 12.8%, based on median hourly earnings of full-time employees only, used by the ONS