Rates of interreligious marriage vary widely: In the United States, it is just under 50%, in the United Kingdom, around 53%; in France; around 30%, and in Australia and Mexico, as low as 10%. In the United States, only about a third of children from intermarriages affiliate with Jewish religious practice. The result is that most countries in the Diaspora have steady or slightly declining religiously Jewish populations as Jews continue to assimilate into the countries in which they live.[citation needed]
Try to answer this question if possible (otherwise reply "unanswerable"): What does not vary by much?
unanswerable