It revealed that the more religious a country is, the lower its students performed in those two key areas. The study shows that there is a negative correlation between the amount of time children spent on religious activities and their educational attainment.
The country rankings are rather interesting. As you might expect the dozen most religious countries are Muslim majority nations. Indonesia and Qatar top the list. The two least religious countries are Japan and the Czech Republic. Sadly the U.S. is the 51st least religious country (32nd most religious). Israel, by the way, is much less religious than we are; ranked as the 23rd least religious.
More information, including charts and the ranking list, at the Daily Mail. A different gauge of religiosity was compiled by Gallup in 2009. It is a larger list that differs in some respects but generally compatible with the new research.