Oracle Database Discussions

Hi,
Oracle 10g R1 and 10gR2.

I have a big table T (30 000 000 rows) I need to split this table to 6 smaller tables.
What is the best way to do it? and the faster way to do it?

Me I use this way but it still very long more than 60min :( and I can stop production more than 20min!!

create table t1 as select * from T where country='US'
create table t2 as select * from T where country='FR'
create table t3 as select * from T where.....
create table t4 as select * from T where.....
create table t5 as select * from T where.....
create table t6 as select * from T where.....

Can you please help?