Qual a percentagem de imigrantes em 2004 no país com 2,1% dos imigrantes em 2006?
CREATE TABLE table_23619212_1 (_percentage_of_all_immigrants_2004 VARCHAR, _percentage_of_all_immigrants_2006 VARCHAR)
SELECT _percentage_of_all_immigrants_2004 FROM table_23619212_1 WHERE _percentage_of_all_immigrants_2006 = "2.1%"