----------------+--------------+--------------
| 9 males | 12 females
+-----+--------+-----+--------
|Cases|Per cent|Cases|Per cent
----------------+-----+--------+-----+--------
Bulging | — | — | 3 | 25
Medium convexity| 6 | 67 | 8 | 67
Rather flat | 3 | 33 | 1 | 8
----------------+-----+--------+-----+--------