Hi Stefen,
Make an initial report with Country wise year and for year give a hyperlink of another report which you want as detail.
For the detail report create a webi with year as prompt and in that report create a variable with year-1 in the adjacent table to show as values for previous year.
Pls check the following document of how to create a hyperlink with selection criteria.
hope it serves your purpose.
BG,
Sundar Kumar