Original sentence: For many visitors from middle-America, Forbidden City was their first encounter with people of Asian ethnicity..  San Francisco's Asian population was approximately 4.2% of the population in 1940, versus 0.2% for all of the United States
Edited sentence: For many visitors from middle-America, Forbidden City was their first encounter with people of Asian ethnicity.San Francisco's Asian population was approximately 4.2% of the population in 1940, versus 0.2% for all of the United States