Many of the commodities seem to have had a consistently decreasing real price prior to the last 100 years. Commodities that look particularly cheap are generally agricultural ones while the more industrial based commodities seem to be at the more expensive end of history, in part fueled by significant demand from China over the past decade. This is particularly true when looking at data over the past 100 years. Precious metals also look expensive from a historical stand-point, which probably reflects the post-1971 fiat currency regime we currently operate in. One of the problems with this analysis is that the importance of these commodities changes over time as does the cost of mining them. Source: Deutsche Bank (2015) - Long-Term Asset Return Study.