1. Sweden (up to 85% non-believer, atheist, agnostic)
   2. Vietnam
   3. Denmark
   4. Norway
   5. Japan
   6. Czech Republic
   7. Finland
   8. France
   9. South Korea
  10. Estonia (up to 49% non-believer, atheist, agnostic)

(Source)

So send your missionaries to Europe, huh?