| Country \(X\) | Country \(Y\) | |||
| (10) | 9766644432 | 80 | ||
| (18) | 888776655544333220 | 81 | 1122333556789 | (13) |
| (16) | 9998877655322100 | 82 | 001233394566788 | (15) |
| (16) | 8765553322211100 | 83 | 01224444556677789 | (17) |
| (11) | 87655443311 | 84 | 001244556677789 | (15) |
| 85 | \(12 r 335566788\) | (12) | ||
| 86 | 01223555899 | (11) | ||
| Number of pupils in a school | \(\leqslant 100\) | \(\leqslant 150\) | \(\leqslant 200\) | \(\leqslant 250\) | \(\leqslant 350\) | \(\leqslant 450\) | \(\leqslant 600\) |
| Cumulative frequency | 200 | 800 | 1600 | 2100 | 4100 | 4700 | 5000 |