Trigger question: ROW or STATEMENT?

Attempting to do my first trigger and I'm confused about which FOR EACH I
should use: ROW or STATEMENT.  I import about 80K rows into an existing
table each day.  If I do a STATEMENT, will the changes only happen on the
new 80K rows I inserted or will it be for all rows in the table - currently
about 12M.

TIA

Patrick Hatcher