They use season avg. price which is not inflation adjusted. From the article:

"These are season average prices, so there would have been higher-than-average prices as well as lower-than-average prices during each marketing year. Consequently the results presented here may overstate the number of years required until a particular "recovery price" was achieved. However, by using averages we can be certain that a particular price actually occurred in that year."



"This raises the question about the consequences of QE."

Steen Jakobson of Saxo bank uses this simple flow chart to explain what he thinks QE impacts are.
 

 Pretend-and-extend to infinity => stronger USD = lower commodity prices = less recycling = higher marginal cost of capital = lower EM growth = less export and more deflation?