| Weekly | 27 % |
| Monthly | 34 % |
| Quarterly | 16 % |
| Only at qualifications | 13 % |
| What? I have to clean it? | 10 % |
| Total | 1622 |
| Weekly | 27 % |
| Monthly | 34 % |
| Quarterly | 16 % |
| Only at qualifications | 13 % |
| What? I have to clean it? | 10 % |
| Total | 1622 |