Gasoline prices have really gone up and down lately. With such wide-ranging short-term fluctuations, it’s hard to tell whether gasoline has become more expensive over the long run. So we turn to FRED. The CPI includes a component that tracks gasoline used for private transportation. We can compare this gasoline component with the CPI to see how gasoline prices have risen in relation to prices in general. The graph clearly shows all the stormy fluctuations for gasoline. But it also clearly shows something we may not have expected: The price of gasoline is now at the same level it would have reached had it simply followed the smooth evolution of the overall price index. We can’t depend on these price levels to coincide, of course, given the typical fluctuations of gasoline. And if the past decade is any indication of the future, gasoline prices will return to their higher levels.

How this graph was created: Search for “CPI gasoline” and select the monthly seasonally adjusted series. Then add the series “CPI.” (You can also work from the relevant release table to select the series you want.) Finally, to start the series at the same level instead of the 1982-84 index year, edit both series as follows: Choose “Index (Scale value to 100 for chosen period)” under Units and “1967-01-01” under Observation Date.

Suggested by Christian Zimmermann