The data are a bit tricky to interpret:
- We only have data from 2005 on, so there isn't much experience with this series.
- The data are not inflation adjusted (no inflation adjustment is documented, and I confirmed by email with the WTO stats people that this is current US$), so presumably if they were, the rises would appear a little less pronounced, and the falls would be a little more pronounced.
- There is some sign of modest seasonality in the data - note how there is generally a bit of an abatement of the trend between Q4 of one year, and Q1 of the next (green circles). However, it's a bit scary to attempt a quantitative seasonal adjustment with so little data and such a huge non-seasonal boom/bust overlaid on it.
Turning to the monthly data, we gain the advantage of data through May 2010, but in addition to the problems of the quarterly data above, we gain the following additional problems:
- There is quite a bit of month-to-month noise
- There is even less data, as it only starts at the beginning of 2006.
- There is missing data in recent months for some countries
Anyway, the resulting monthly series are here:
You can see that the drop-off in Q1 is made up of a very strong drop in Jan/Feb, followed by a strong rebound in March. Then April and May declined from there.
Given the difficulties of interpreting the data, I don't want to draw too strong a conclusion here. It's certainly consistent with the idea that the global economy is starting to contract again, but the data are too noisy to consider this as strong additional evidence at present.