| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| 1 | Annually | 7 | 
                                    
                                    5.9%
                                 | 
| 2 | Biannually/Every six months | 3 | 
                                    
                                    2.5%
                                 | 
| 3 | Quarterly | 2 | 
                                    
                                    1.7%
                                 | 
| 4 | Monthly | 96 | 
                                    
                                    80.7%
                                 | 
| 5 | Weekly | 4 | 
                                    
                                    3.4%
                                 | 
| 6 | Daily | 5 | 
                                    
                                    4.2%
                                 | 
| 7 | Hourly | 0 | 
                                    
                                    0%
                                 | 
| 8 | More than once in an hour | 2 | 
                                    
                                    1.7%
                                 | 
| Sysmiss | 836 |