Senegal, Pakistan and Afghanistan, among the world’s 50 poorest nations, are turning to Islamic banking to spur economic growth by encouraging people to take out loans and open savings accounts. Developing Islamic nations have shunned banking in part because of the religion’s ban on interest, limiting access to funds for project financing and stunting business growth, according to the International Monetary Fund. The concept of risk-sharing in Shariah banking that prohibits interest payments would be more useful in Muslim countries because their economies are less diversified, the IMF economists said.