4. (20 points) For this question you can choose between using Excel or R. Using data from the Penn World Tables (Link: https://www.rug.nl/ggdc/productivity/pwt/), please complete the following: (a) Replicate Table (2.1) of the textbook, adding an extra column for the period 2010-2018. Comment on your findings. (b) Replicate Table (2.1) of the textbook, but for Canada instead of USA. Comment on your findings. Provide your Excel file or R. script. Please see the footnote for hints