Chuck Blow wrote an article for the New York Times, Religious Outlier, where he showed that nations where people feel that religion is part of their everyday lives are strongly correlated with poor economic performance. The United States is a bizarre outlier on this chart. It is wealth and religious. Almost all of the very religious nations are dirt poor. Many religions teach that "this world" is not important and that only god is important. That cannot lead to good results in terms of scientific and cultural progress. The religious zealots who came to America were an odd bunch, even for religious zealots. They created the famous "Protestant Work Ethic" and the results have been nothing less than phenomenal. In most other cases, religion seems to lead people and nations to destitution.
The most religious states (the Bible Belt) are the poorest in the US though: http://en.wikipedia.org/wiki/List_of_U.S._states_by_income Apparently the Jews are the most wealthy religious group in the US: http://researchnews.osu.edu/archive/relgwlth.htm but I would say that those rich ones aren't really all that religious, and that the most religious Jews (the ultra-Orthodox, or Haredim) is probably the poorest group out of all US Jews. I don't have evidence for this but they are the most poor group in Israel with the highest number of unemployed.
I don't see China on the list of 114 countries in the Gallup Poll. Please check, I may be missing it. It's just about nap time here at the old folks home. It does seem that, according to this data, socialism is a religion.
It's no surprise that islamic countries are some of the poorest on the planet. Half of their population aren't allowed to work, they have to stop working many times a day to stick their ass in the air and wail to a magic sky man and they participate in Ritualistic starvation, which includes not taking medication. None of these things are conducive with productivity. Even in England they have a work-shy tendency. Give them an opportunity to opt out of doing their job by pretending their religion forbids it and they are lining up around the block waiting to opt out. I think the problem is because they originate from unproductive countries they tend to lack any kind of work ethic. They don't feel compelled to actually do the thing they are being paid to do if they are given an opportunity to skive off.