| Value | Category | Cases | |
|---|---|---|---|
| 1 | Are taken directly from establishment records | 285 | 
                                    
                                    70.9%
                                 | 
| 2 | Are estimates computed with some precision | 68 | 
                                    
                                    16.9%
                                 | 
| 3 | Are arbitrary and unreliable numbers | 2 | 
                                    
                                    0.5%
                                 | 
| 4 | Are in some case taken from books and in some case estimates | 47 | 
                                    
                                    11.7%
                                 |