Question: By 1931, what percentage of the world's Jews were the group of Jews that represented the bulk of modern Jewry?

Knowledge 1: Jews
Ashkenazi Jews represent the bulk of modern Jewry, with at least 70% of Jews worldwide (and up to 90% prior to World War II and the Holocaust). As a result of their emigration from Europe, Ashkenazim also represent the overwhelming majority of Jews in the New World continents, in countries such as the United States, Canada, Argentina, Australia, and Brazil. In France, the immigration of Jews from Algeria (Sephardim) has led them to outnumber the Ashkenazim. Only in Israel is the Jewish population representative of all groups, a melting pot independent of each group's proportion within the overall world Jewish population. [SEP] Knowledge 2: Ashkenazi Jews
Of the estimated 8.8 million Jews living in Europe at the beginning of World War II, the majority of whom were Ashkenazi, about 6 million – more than two-thirds – were systematically murdered in the Holocaust. These included 3 million of 3.3 million Polish Jews (91%); 900,000 of 1.5 million in Ukraine (60%); and 50–90% of the Jews of other Slavic nations, Germany, Hungary, and the Baltic states, and over 25% of the Jews in France. Sephardi communities suffered similar depletions in a few countries, including Greece, the Netherlands and the former Yugoslavia. As the large majority of the victims were Ashkenazi Jews, their percentage dropped from nearly 92% of world Jewry in 1931 to nearly 80% of world Jewry today. The Holocaust also effectively put an end to the dynamic development of the Yiddish language in the previous decades, as the vast majority of the Jewish victims of the Holocaust, around 5 million, were Yiddish speakers. Many of the surviving Ashkenazi Jews emigrated to countries such as Israel, Canada, Argentina, Australia, and the United States after the war.
Knowledge 1: Jews
Ashkenazi Jews represent the bulk of modern Jewry, with at least 70% of Jews worldwide (and up to 90% prior to World War II and the Holocaust). As a result of their emigration from Europe, Ashkenazim also represent the overwhelming majority of Jews in the New World continents, in countries such as the United States, Canada, Argentina, Australia, and Brazil. In France, the immigration of Jews from Algeria (Sephardim) has led them to outnumber the Ashkenazim. Only in Israel is the Jewish population representative of all groups, a melting pot independent of each group's proportion within the overall world Jewish population. [SEP] Knowledge 2: Ashkenazi Jews
It is estimated that in the 11th century Ashkenazi Jews composed only three percent of the world's Jewish population, while at their peak in 1931 they accounted for 92 percent of the world's Jews. Immediately prior to the Holocaust, the number of Jews in the world stood at approximately 16.7 million. Statistical figures vary for the contemporary demography of Ashkenazi Jews, oscillating between 10 million and 11.2 million. Sergio DellaPergola in a rough calculation of Sephardic and Mizrahi Jews, implies that Ashkenazi make up less than 74% of Jews worldwide. Other estimates place Ashkenazi Jews as making up about 75% of Jews worldwide.
Knowledge 1: Ashkenazi Jews
Of the estimated 8.8 million Jews living in Europe at the beginning of World War II, the majority of whom were Ashkenazi, about 6 million – more than two-thirds – were systematically murdered in the Holocaust. These included 3 million of 3.3 million Polish Jews (91%); 900,000 of 1.5 million in Ukraine (60%); and 50–90% of the Jews of other Slavic nations, Germany, Hungary, and the Baltic states, and over 25% of the Jews in France. Sephardi communities suffered similar depletions in a few countries, including Greece, the Netherlands and the former Yugoslavia. As the large majority of the victims were Ashkenazi Jews, their percentage dropped from nearly 92% of world Jewry in 1931 to nearly 80% of world Jewry today. The Holocaust also effectively put an end to the dynamic development of the Yiddish language in the previous decades, as the vast majority of the Jewish victims of the Holocaust, around 5 million, were Yiddish speakers. Many of the surviving Ashkenazi Jews emigrated to countries such as Israel, Canada, Argentina, Australia, and the United States after the war. [SEP] Knowledge 2: Jewish Historical Museum, Belgrade
It focuses on Belgradian Jews from the 2nd century until World War II, encompassing the lives of Jews who lived in Serbia and Yugoslavia. There is a predominance of memorial displays as well as a large collection of documents and photographs which attest to the Holocaust in which many Jewish families were totally decimated.

Answer: 92 percent