1924 marked the beginning of the Fourth Aliyah. That year, 12,000 new immigrants arrived in Palestine compared with the 6,000 of the three preceding years. In 1925, immigration rose to 35,000. These immigrants were Unlike the early settlers, who had been young and primarily single, these newcomers were primarily married and middle class; many of substantial means. This marked the beginning of the development of industry in Palestine. By 1926, immigration slackened off, and by the close of the decade, Palestine was immersed in economic crisis. Emigration exceeded immigration for a number of years.