| Value | Category | Cases | |
|---|---|---|---|
| 1 | Distributor | 23 | 
                                
                                10.8%
                             | 
| 2 | School | 9 | 
                                
                                4.2%
                             | 
| 3 | Any source | 142 | 
                                
                                67%
                             | 
| 5 | Missing | 1 | 
                                
                                0.5%
                             | 
| 6 | Other: Both school and distributor | 4 | 
                                
                                1.9%
                             | 
| 9 | Not applicable | 33 | 
                                
                                15.6%
                             |