How are they to believe in Him of whom they have never heard?

In the Christian (reached) world there are 2,100 full-time Gospel workers for every one million people.

In the unreached world there are six foreign missionaries for every one million people.

This video from the Beautiful Feet Project:

Beautiful Feet Project from AsiaLink HistoryMaker on Vimeo.

How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching? And how are they to preach unless they are sent? As it is written, “How beautiful are the feet of those who preach the good news!” But they have not all obeyed the gospel. For Isaiah says, “Lord, who has believed what he has heard from us?” So faith comes from hearing, and hearing through the word of Christ.
—Romans 10:14-17