Believe it or not, among wealthy countries America is the most altruistic: The World Values Survey asked people how important it was to them to serve others. The following is the percent who answered "very important":

Percent saying serving others is very important to them:
Puerto Rico 78.8
Morocco 67.8
Venezuela 67.7
Jordan 67.0
Mexico 63.6
Iran 62.1
Nigeria 62.0
Egypt 61.8
Tanzania 58.6
Philippines 57.5
Argentina 56.6
Chile 53.4
USA 51.2
Peru 49.4
South Africa 49.2
Uganda 47.9
Bangladesh 46.8
India 46.6
Canada 42.4
Saudi Arabia 40.8
Serbia 37.9
Sweden 37.3
Indonesia 36.5
Pakistan 33.2
Moldova 32.2
Spain 30.2
Kyrgyzstan 25.4
Albanian 19.9
Bosnia and Herzegovina 17.6
Vietnam 16.2
Singapore 15.9
China 15.6
Macedonia 14.5
Montenegro 13.3
Korea 10.8
Japan 8.6

The regional pattern: East Asia and SE Europe, low; Latin America, Muslim, and African, high; and developed countries, moderate. It's interesting that an altruistic spirit has little to do with how well a country actually serves the needs of its people. The service-oriented nations in the list generally do a poor job. In fact, Japan and Korea--the last two on the list--have produced successful societies without a strong feeling of duty to others. Western countries have created high levels of well-being with only very moderate amounts of altruism.

And while the United States has the reputation of a gang of heartless capitalists, it ranks as the most service-minded country among developed nations.

I can examine this more systematically when I have finished building a data set, but these patterns might reflect the religious culture of the people. The Catholic Church may have taught Puerto Ricans to believe in the importance of serving others, even if they don't always do it. On the other hand, Japanese people might be good neighbors, even though they don't have the same kind of religious culture.