Only since the 1940s when the United States and China became allies during World War II, did the situation for Chinese Americans begin to improve, as restrictions on entry into the country, naturalization and mixed marriage were lessened. In 1943, Chinese immigration to the United States was once again permitted—by way of the Magnuson Act—thereby repealing 61 years of official racial discrimination against the Chinese. Large-scale Chinese immigration did not occur until 1965 when the Immigration and Nationality Act of 1965 lifted national origin quotas. After World War II, anti-Asian prejudice began to decrease, and Chinese immigrants, along with other Asians (such as Japanese, Koreans, Indians and Vietnamese), have adapted and advanced. Currently, the Chinese constitute the largest ethnic group of Asian Americans (about 22%), and have confounded earlier expectations that they would form an indigestible mass in American society. For example, many Chinese Americans of American birth may know little or nothing about traditional Chinese culture, just as European Americans and African Americans may know little or nothing about the original cultures of their ancestors.