Another useful measure of Americans’ beliefs about the state of the economy is the age at which they believe they will retire. If non retired people believe that they will need to work longer to be able to afford their lifestyle after retirement it likely means that their confidence in the economy is not high. A Gallup survey conducted every 5 years starting in 1996 asked nonretired U.S. adults to predict at what age they would retire.

a. Can we infer that the predicted age of retirement has fluctuated over the years?

b. If differences exist which years differ?