| Value |
Category |
| 0 |
No data from individual questionnaire |
| 1 |
Month and year |
| 2 |
Month and age -y imp |
| 3 |
Year and age - m imp |
| 4 |
Y & age - y ignored |
| 5 |
Year - a, m imp |
| 6 |
Age - y, m imp |
| 7 |
Month - a, y imp |
| 8 |
None - all imp |
Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.
