Basically all Muslims east, north and south of Saudi Arabia are all descendents of converts who were forced into converting to Islam. I could be wrong about a few; but Afghanistan, Iran, Pakistan, India, Bangladesh, and points east, including Malayasia and Indonesia, were all either Hindus, Buddhists, or animists of one sort or another. (A few Jains and other sorts here and there.)
If only it wasn't against Muslim law for them to convert back!