| Value |
Category |
| 0 |
No special system |
| 1 |
Calendar |
| 2 |
Body temperature |
| 3 |
Cervical mucus |
| 4 |
Body temp. & mucus |
| 5 |
Other |
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.
