"To speak only of absolute amounts is meaningless."
only if you consider socioeconomic policy meaningless. get a crackpot dictator to drive any semblance of an economy into the ground with corruption, regulation and isolationism, and $100 looks like a significant chunk of the GNP. If you want to start playing games with what metrics of charity are meaningful, you need to consider ALL factors, including what resulted in a nation or nations being ill-prepared to financially handle a natural disaster. hell... the U.S. is nearly 8 TRILLION dollars in debt, but we are somehow prepared to handle our own disasters and others?
"...you need to consider ALL factors..."
Certainly, and it's near impossible to be 100 percent accurate. My suggestion is not perfect and you mention other factors that could be considered, but it's better than ranking by absolute dollar amounts. By this logic, George Soros could theoretically be considered more generous than the entire United States if he chose to give a few hundred million dollars.