| Type of structures in main titles | IJs | DJs | DE | |||
| n | % | n | % | n | % | |
| Noun phrase | 161 | 80 | 193 | 96 | 92 | 92 |
| Gerund | 21 | 10 | 7 | 4 | 5 | 5 |
| Question form | 8 | 4 | 0 | 0 | 0 | 0 |
| Statement | 7 | 4 | 0 | 0 | 3 | 3 |
| Preposition | 3 | 2 | 0 | 0 | 0 | 0 |