Notation	Name	Description	Status
1	Data groups missing due to radio fading		stable
2	Data groups missing due to outage of centre		stable
3	Data groups missing due to outage of circuit		stable
4	Non-implementation or maintenance of required RBSN density		stable
5	Shortage of qualified staff to man stations		stable
6	Lack of consumables		stable
7	Instrument failure		stable
8	Non-adherence to telecommunication procedures		stable
9	Some observing programmes ceased		stable
15	Missing value		stable