In 1922, the Federal Reserve Board began offering its industrial production index, with data starting in January 1919—which means we now have 100 years of data!
This series has been extremely useful in helping us gauge the state of the economy: At first, industrial production was basically the only data series available before the computation of GDP; and the data are published more frequently and quickly than GDP data. The disadvantage is that industrial production doesn’t encompass the entire U.S. economy. In fact, it has encompassed less and less as the economy has matured into primarily a service economy.
How this graph was created: Search for “industrial production” or click on “industrial production” on the FRED homepage.
Suggested by Christian Zimmermann.