After 500 years of deliberate disinformation, you may find this interesting: The Truth About the Spanish Inquisition. Dude, that's very selective history. As a Sephardi myself, I can tell you I've encountered numerous people who were RAISED as Anusim/Morranos/Conversos. Yes, they stayed secret Jews for 500 years. There were entire villages in Portugal and Latin America of hidden Jews. The vast majority of conversos, at least originally, were not sincere converts but Jews forced into Catholicism by persecution.
Also, the total number of pre-expulsion Jews in Spain was more like 250,000.
Although I believe the historical account in my link to be objective, it is important to remember that the history of the Spanish Inquisition was severely exaggerated as part of a deliberate propaganda campaign. As you seem to know, it was aimed at the Conversos, not the Jews who had publically refused conversion. Although there was a great injustice in how many people may have been displaced, only about 4,000 were ever executed.