| Value | Category | Cases | |
|---|---|---|---|
| 1 | Are taken directly from establishment records | 39 | 
                                                                 
                                    
                                    22.5%
                                 
                                                             | 
                                                        
                    
| 2 | Are estimates computed with some precision | 33 | 
                                                                 
                                    
                                    19.1%
                                 
                                                             | 
                                                        
                    
| 3 | Are arbitrary and unreliable numbers | 2 | 
                                                                 
                                    
                                    1.2%
                                 
                                                             | 
                                                        
                    
| 4 | Are in some case taken from books and in some case estimates | 99 | 
                                                                 
                                    
                                    57.2%
                                 
                                                             |