How? The trends represent real-world data. And, before anyone says anything about fear of Islam or Judaism, Jews don't want people converting to their faith -- it's why they don't proselytize. They believe you have to be born into it. And most Muslim converts, who weren't born into the religion, leave it within 5 years anyway. There's no reason to fear either taking over anything from conversions.
I just want to know what's going on behind the scenes.