Answer to Question #153034 in Macroeconomics for juliana

Question

The natural unemployment rate in the United States has varied over the
last 50 years. According to the Congressional Budget Office, the natural
rate was 5.5% in 1960, rose to about 6.5% in the 1970s, and had declined
to about 4.8% by 2000. What do you think might have caused this
variation?

Answer 1

The changes in the natural unemployment rate in the United States were caused by two main reasons: 

1) as a result of the population growth in the postwar years or the so-called baby boom in the 1970s the share of young working people increased. Since young workers have a higher unemployment rate than older workers, the aggregate unemployment rate rose then.

2) due to the aging baby boomer generation the natural unemployment rate decreased by 2000.