Of the 188.0 million persons 1 year old and over living in the United States in March 1965, 37.9 million, or 20.1 percent, had been living at a different address in the United States in March 1964. An additional 0.5 percent has been living abroad in March 1964. The proportion of the population that moved within the country, according to the 18 annual surveys conducted since 1948, ranged from 18.6 to 21.0 percent, a relatively small variation. Between March 1964 and March 1965 about 13.0 percent of the population moved within counties, 6.8 percent moved between States.