St. Mechtilde believed that Our Lord said to her that the number of Catholics who go to Heaven when they die, exceeds the number of those who go to Hell (Liber specialis gratiae. In Sanctae Mechtildis, virginis ordinis sancti Benedicti, Liber specialis gratiae accedit sororis Mechtildis ejusdem ordinis Lux divinitatis. Book 6, Chapter 15. Ed. Monks of Solesmes. Paris: Oudin, 1877). Nevertheless, Our Lord assured her that His justice will claim its due; many souls will go to Purgatory before they are pure enough to enter the Kingdom of God.
Whether or not we can apply this revelation to every generation is not certain (private revelations, in themselves, are uncertain*). It may be the case that the majority of Catholics will, in the end, be saved.
Either way, let us thank God for His mercy! And let us not be presumptuous! We will be saved if we seek God with all our heart. If we are tepid in our faith, there is a danger that we will fall from sin to sin, without even realising how far we have fallen. We must imitate the holy monk that St. Leonard tells us about, who said that, even if one soul were damned, he would do absolutely everything in his power not to be that soul.
*Still, if they are consistent with Church teaching, and if they have been given to a humble and obedient soul, such as St. Mechtilde, then we are safe in believing them, so long as we subordinate them to the Magisterium… This site only quotes from the revelations of those whose virtue has been recognised by reputable authorities.
The Eternal Father to St. Hildegard:
“Does anyone think it possible to see into the deep wisdom of the Most High and into the discernment of His knowledge, and count the number of those who are to be saved? His judgements are incomprehensible to all people. Your task is to run; for the kingdom of God is prepared for you.” (p. 315, Scivias)
Littlest Souls 