Using the data on the CountryPopulations worksheet create a PivotTable with a calculated item to show the population of North America. Insert the PivotTable on the NorthAmerica worksheet. Place Country as the row labels. Use an appropriate presentation of the Population as the PivotTable values to display the total population for each country. Add the a calculated item named "NorthAmerica" (without the quotes) to the Country field to calculate the population of North America. Note that North America includes the countries of Canada, Mexico, and the United States