+0

Overall, percentages of people in all three groups (men, women, and children) displayed a broadly similar pattern, climbing steadily to reach an all-time high in 2006 for the first two groups and in 2007 for children before dipping slightly.

Is this sentence grammatically correct?

+1

The grammar is OK, except I'd add a a comma before before dipping slightly, to indicate that the dip refers to all groups, not just to children.

The meaning is not very clear without more context. For example, we don't know what the percentages indicate.

Clive