Table schema:
CREATE TABLE table_23619212_1 (_percentage_of_all_immigrants_2004 VARCHAR, _percentage_of_all_immigrants_2006 VARCHAR)

Question: What's the percentage of immigrants in 2004 in the country with 2.1% of the immigrants in 2006?
SQL: SELECT _percentage_of_all_immigrants_2004 FROM table_23619212_1 WHERE _percentage_of_all_immigrants_2006 = "2.1%"