That graph is flawed. The right vertical axis (1929) is a factor of 2. The left side (today) is about .33. If the slopes were compared with the same scale, there would be no comparison.
is that a graph of the harvest of DJIA fruit from far flung Borneo over the last two years vs that in 1928-29? The rainfall must have been similar but i thought that improvements in technology would have raised the productivity somewhat. Pretty disappointing for the Borneoese.
The other flaw in that graph is that it stops where it stops. Which isn't today. So, if you carried on plotting it out, the lines cross and the correlation - impressive, no doubt, if only a trick of the y-axis scale - is lost.