I wonder how much other things like urbanisation need to be controlled for. Eg skimming Wikipedia, over 40% of canadas population is in urban areas with a popul

I wonder how much other things like urbanisation need to be controlled for. Eg skimming Wikipedia, over 40% of canadas population is in urban areas with a population over 500k whereas the percentage for the US is much lower. (Though my guess is that different classifications for ‘urban area’ mess up my quick counting). For example if you plotted similar lines for each of the nine census divisions in the US, how much of an outlier would Canada still look like? What if one tried to make some synthetic Canada-like regions of the us where people are more clustered in big cities? It seems plausible to me that Canada would still stick out, but I’m not sure by how much.