Past perfect optional???

[sonu_gmat]

In 1950 Country X exported more of its national products than it did in 1940.

Don't we need past perfect in the above sentence. The problem from where I rephrased it has this choice as OA. I read some where if we have 'before' or 'after' clearly stating the sequence of events in a sentence use of past perfect could be optional. Does that rule apply here also since it clearly states the time.

[esledge]

That's exactly what's going on. The dates clearly indicate which past action happened first, so you can safely use past tense for each.