| Value | Category | Cases | |
|---|---|---|---|
| 1 | Are taken directly from establishment records | 175 | 
                                    
                                    17.1%
                                 | 
| 2 | Are estimates computed with some precision | 759 | 
                                    
                                    74.1%
                                 | 
| 3 | Are arbitrary and unreliable numbers | 34 | 
                                    
                                    3.3%
                                 | 
| 4 | Are in some case taken from books and in some case estimates | 56 | 
                                    
                                    5.5%
                                 |