1)How many recessions have there been in the US economy since 1959? When did the most recent US recession begin (peak) and end (trough) ( this is not a trick question

1)How many recessions have there been in the US economy since 1959? When did the most
recent US recession begin (peak) and end (trough) ( this is not a trick question. this question refers to the most recent complete recession)?

2)When was the longest post World War 2 business cycle expansion in the US? (trough to peak, give the trough and peak dates, again this refers to the complete expansion)

3)When was the deepest post World War 2 recession in the US? (peak to trough, give the peak and trough dates)

4)Why do we need seasonally adjusted data to analyze business cycles? Provide examples.