One reason why a country might have a larger Jewish population was because during 1933 to 1941, Nazi Germany was on a rampage and evicted millions of Jewish families from their homes. These families then fled to many other countries seeking safety from Germany. Many Jewish families were trying to immigrate to the U.S, but many didn't didn't get permitted to because the U.S had already taken in a lot of refugees and were worried about their national security and economy.
Another reason is that culturally, I think Jewish families are multigenerational households, which means that more than just the nuclear family live under the same roof. I could be wrong about this, but I am pretty sure that it was this way, but maybe that was just back then.
The only shape that casts a round shadow no matter which direction it is pointed is a sphere, and the ancient Greeks deduced that this must mean the Earth is spherical.
