About 45% of the world's Jews live in Israel. Another 40% live in the USA. Of course who is a Jew and how you count them is a bit unclear, for example people with Jewish fathers and non-Jewish mothers (and there are quite a few of them) clearly have a connection to Judaism even if they are not officially Jewish. I know that in England official figures represent the number of Jews registered with a Synagogue but nobody in my family is remotely orthodox or registered with a Synagogue and yet here I am living in Israel.
One thing is clear: Since the Second World War, there has been a massive shift in Jewish demographics, and part of that shift has been a movement towards English speaking countries. Millions have left Arab, Moslem and East European countries and moved to Israel and the USA, Canada or Australia. Mainly of course, to the Israel and the USA. Of the top ten Jewish communities in the World, four are English speaking and the other is Israel.
Of the other significant communities: Argentina, Russia and France experience migration (mainly to the USA or Israel) and only Brazil and Germany experience growth but have only small populations.
Assuming current trends continue, by the end of the century nearly all the world's Jews will speak English or Hebrew and many, perhaps most, will speak both as Jews migrate between Israel and English speaking countries. Jews frequently migrate to Israel and then from Israel, they or their children move to the USA or vice versa.
The other significant change is the rapid irrelevance of the Ashkenazi-Sephardi divide. It used to be that if a Jew came from Europe s/he was Ashkenazi and if they came from the Middle East they were Sephardi. That is to say your place of residence defined your Jewish sub-ethnicity. Nowadays most French Jews (half of Europe's Jews live in France) are "Sephardi" and originate from Algeria or Tunisia, while any Jew from the Middle East is an Israeli and could be anything. That means the Ashkenazi Sephardi distinction now only relates to Synagogue affiliation and history, and that is meaningless for Secular Jews and of low significance among Modern Orthodox Jews Only Haredi Jews still maintain the distinction and I suspect that even among them, distinctions are eroding in Israel, as some secular Jews from different origins become Haredi and as social gaps erode.
According to Meir Shitrit on the Ministry of Education's website, over 35% of Israeli marriages are between Sephardi and Ashkenazi partners while a Hebrew University study found that the percentage of children with mixed parentage increases by half a percent each year as children get younger, with 15 year olds currently at about 25% born or intermarriage. Incidentally, this means that over time all Israelis will be descended from both Holocaust survivors and from Jews who were evicted/escaped the Arab world. There are also sizeable groups such as "Bukharan"s (Uzbekistani and Kazakhstani Jews), Caucasians (eg from Armenia, Azerbaijan,Georgia etc.) and Bulgarians, Turks, Indians and Ethiopians who are neither Ashkenazi or Sephardi. Needless to say members of all Jewish groups live in the USA, where differences erode even faster.
Among Haredi Jews change is much slower; Marriages are arranged and tend to remain within the different Hassidic "courts", but the same processes occur among them, its just the speed that is slower.