First, about the Muslim countries. There’s a teaching in hadits (Mohammad’s wisdom, lower than Quran but is also referred) that the sin that Allah hates the most is suicide. This alone puts some break on suicidal intention. That social control and integration are stronger in this countries also reduce the rate (the same argument was used by Emile Durkheim in his famous book on suicide). He further argued that in some countries people where integration is low, people suffer from anomie. They’re not sure what values to follow.
Second, Christian values are not necessarily practiced in those Christian countries. Some form of existentialism that is close to nihilism is quite strong. Without any meaning in this world, why should one continue to live?
Third, in some countries like S. Korea, pressure from expectations leave people stressed out if those expectations are not met. With achievement is connected with pride, no achievement means living in shame. Taking own life is one way to escape.
Good arguments and explanation. Thank you
Fourth, if you add honor killing into the mix Muslims are off the charts.