Bob Murphy pointed this out a few months ago on his blog (link not available due to unresolved search engine-related issues), but I thought I’d try to make the point a different way:
Barrels of Oil which could be bought with an Average Hour of Production and Nonsupervisory Worker Earnings

And people wonder why first-world growth was so much slower after 1973. Good thing I brought my keyboard, mouse, and USB jack with me to plug into my tablet while in Russia, as these enable me to compose posts much more quickly.