well, supposedly the proportion of saved vs damned, according to what The Apocalypse of Yajnavalkya indicates (i forget now - have read it twice but can't remember the justification for this) is the same as it was during the War in Heaven, ie, 1/3 are fallen

so that actually suggests that it's not about which religion you follow, it's that you follow the Law that Christ brings, and Jesus and numerous other writers in the New Testament say this as well, even the Qur'an says that who follows the Law of Allah is a muslim (one who follows the way of peace)