Different from the previous Jewish immigrations to Palestine, this Aliyah is driven by economic forces, primarily in Poland, and the restrictions on immigration to the United States in 1924. Improved economic conditions in Palestine make it more attractive to immigrants. While 67,000 immigrants come durring this period, several thousand leave in 1927 due to economic hardships. Most of those who arrive invest their own savings in new enterprises indicating a commitment to the Zionist enterprise.