| Code Figure | Meaning | 
|---|---|
| 0 | 
      No explicit missing values
included within the data values | 
    
| 1 | 
      Primary missing values included within the data values | 
| 2 | 
      Primary and secondary missing values included within the data values | 
| 3-191 | 
      Reserved | 
| 192-254 | 
      Reserved for Local Use | 
    255 | Missing |