I found the per calculation highly suspicious, especially the first row:
> Country Median Margin Average Margin Sample Size > South Africa 28.86% 82.37% 7
How can the average be 82% with a median being 28% without having one that is above 100%?
> Country Median Margin Average Margin Sample Size > South Africa 28.86% 82.37% 7
How can the average be 82% with a median being 28% without having one that is above 100%?
It being a weighted average does sound like a reasonable explanation, though. A median of 0.29 and weighted mean of 0.82 is trivially possible given e.g. values (0.29, 0.29, 0.82) and weights (0, 0, 1).