According to the Jewish Virtual Library, Europe has 2.3 million Jews, and 11 of the 20 countries with the biggest Jewish populations are in Europe: Russia, France, the United Kingdom, Ukraine, Germany, Belarus, Hungary, Belgium, Spain, the Netherlands and Moldova.
By contrast, among predominately Muslim countries, the one with the biggest Jewish population is Iran itself, which places 25th with an estimated 20,405 Jews. This is less than one-fifth of Germany's Jewish population, and other estimates (such as this one) have the number much smaller.
The only other majority-Muslim countries to crack the top 50 are Turkey (17,415 Jews), Azerbaijan (7,911), Morocco (5,236) and Kazakhstan (4,100). The depopulation of Jews from the Arab and Muslim worlds is largely a postwar phenomenon; according to the JVL, Iraq's Jewish population had declined to around 100 by 2003 from 150,000 in 1948:
After the establishment of Israel in 1948, Zionism became a capital crime.
In 1950, Iraqi Jews were permitted to leave the country within a year provided they forfeited their citizenship. A year later, however, the property of Jews who emigrated was frozen and economic restrictions were placed on Jews who chose to remain in the country. . . .
In 1952, Iraq's government barred Jews from emigrating and publicly hanged two Jews after falsely charging them with hurling a bomb at the Baghdad office of the U.S. Information Agency.
With the rise of competing Ba'ath factions in 1963, additional restrictions were placed on the remaining Iraqi Jews. The sale of property was forbidden and all Jews were forced to carry yellow identity cards. After the Six-Day War, more repressive measures were imposed: Jewish property was expropriated; Jewish bank accounts were frozen; Jews were dismissed from public posts; businesses were shut; trading permits were cancelled; telephones were disconnected. Jews were placed under house arrest for long periods of time or restricted to the cities.