Question: When did the country that produced 1,213,000 (21st) bbl/day join Opec?
Schema: create table table_166346_1 (joined_opec varchar, production___bbl__day_ varchar, PRIMARY KEY (joined_opec))
SQL: select joined_opec from table_166346_1 where production___bbl__day_ = "1,213,000 (21st)"