| Value | Category | 
|---|---|
| 1 | I did not smoke cigarettes during the past 30 days (one month) | 
| 2 | Less than 1 cigarette per day | 
| 3 | 1 cigarette per day | 
| 4 | 2 to 5 cigarettes per day | 
| 5 | 6 to 10 cigarettes per day | 
| 6 | 11 to 20 cigarettes per day | 
| 7 | More than 20 cigarettes per day | 
| Sysmiss |