My pastor loaned me a book a while back written by C.I. Scofield that was titled "Prophecy made plain". In it he wrote that at that time, ~ 1900 AD, there were over 800,000 ppl who had not heard the gospel. In Turkey, my pastor told me this(and he ain't no Calvinist, either), it is against the law to be a christian. Last summer a Gideon came and said that over a billion ppl in India have not heard the gospel. And he's not a Calvinist, either.
There have been many died, never knowing about the Christ. Anyone would be foolish to say everyone w/o exception has heard the gospel.