| Value | Category | Cases | |
|---|---|---|---|
| 1 | Are taken directly from establishment records | 274 | 
                                    
                                    45.7%
                                 | 
| 2 | Are estimates computed with some precision | 127 | 
                                    
                                    21.2%
                                 | 
| 3 | Are arbitrary and unreliable numbers | 1 | 
                                    
                                    0.2%
                                 | 
| 4 | Are in some case taken from books and in some case estimates | 198 | 
                                    
                                    33%
                                 |