The hint to that is also in the Orthodox distribution. Why from all the Christian denominations they are the wealthiest? I think that big part of Jewish and Orthodox populations comes from ex-Soviet republics. Strong emphasis on education back over there and immigrant need to prove themselves will cause such skewed statistics. You know what more? I think the Jewish stats are brought down by Orthodox Jews that have +10 kids and spend their lives studying Torah and don't worry that much about making money( I understand that some Muslims and Christians are like that but it's less common ).