| Value | Category | Cases | |
|---|---|---|---|
| 1 | Are taken directly from establishment records | 37 | 
                                    
                                    32.5%
                                 | 
| 2 | Are estimates computed with some precision | 33 | 
                                    
                                    28.9%
                                 | 
| 3 | Are arbitrary and unreliable numbers | 3 | 
                                    
                                    2.6%
                                 | 
| 4 | Are in some case taken from books and in some case estimates | 41 | 
                                    
                                    36%
                                 |