16.4 The data file Government Net Lending Euro Area contains the time series of general government net lending as a percent of GDP for the Euro area countries.

The dataset covers the period 2002:Q1 up to 2019:Q4, for a total of 72 quarters.

a. Plot the time series, and discuss its features. Is a seasonal adjustment warranted?

b. Use the seasonal-index method to seasonally adjust this series. Graph the seasonally adjusted series, and discuss its features. [Hint: It is advisable to do the seasonal adjustment on a new series, defined as the original series plus 10, to avoid the impact of negative numbers. You should then subtract 10 from the adjusted series to undo the addition and convert the numbers to the correct (original) scale.]