Restriction of immigration during the 1920s marked a significant change in American policy. During the first 15 years of the 20th century, over 13 million people had come to the United States. For some time, public sentiment against unrestricted immigration had been growing. The United States no longer thought of itself as having a great internal empire to settle, and it was no longer willing to accept vast hordes of immigrants. This sentiment expressed itself in a series of measures culminating in the Immigration Quota Law of 1924 and a 1929 Act. These limited the annual number of immigrants to 150,000, to be distributed among peoples of various nationalities in proportion to the number of their countrymen already in the United States in 1920. Thus, immigration was made selective, since the stream now largely came from southern and eastern Europe instead of from the north and west. By drastically limiting numbers, the measure curbed one of the great population movements of world history, a process three centuries old.