Japan's justice ministry reported that as of 31 December 2010, the census for foreigners (gaijin or more appropriately, gaikokujin) living in the country went south for the second consecutive year.
A decrease of 2.4 percent (51,970) was noted from 2009's 2,134,151 registered foreigners, according to Kyodo News.
An official from the ministry attributed the shrinking foreigner population to the mass layoffs of major companies since the worldwide economic crisis in the late 2008.
In 2008, the foreigners comprised 1.6 percent of Japan's 127.3 million population. The Chinese, Koreans and Brazilians were the three largest groups of foreigners in the country that constitute 29.6, 26.6 and 14.1 percent, respectively.
This was followed by the Filipinos (9.5 percent), Peruvians (2.7 percent) and Americans (2.4 percent), according to Wikipedia.
Whereas the Chinese population in Japan grew by one percent, the Korean and Brazilian groups has gone down by 2.2 and 13.8 percent, respectively.
It should be noted that the above report did not include the twin disasters on 11 March this year.
In another report by the justice ministry, the entry/exit ratio between 5 March and 8 April was 68 percent. Meaning, of the 671,000 foreigners who left the country during the specified time period, 458,000 came back according to Tokyo Times.
In descending order, the foreign nationals who left Japan after the tsunami were the Chinese, South Koreans, Americans, Taiwanese, Filipinos, Thais, Australians, British, Hong Kongers, and Indians.
Details of this report here.