does "select count(*) from mytable" always do a seq scan?

Hi,

I am using Postgresql 7.4.  I have a table with 1.5 million rows.  It
has a primary key. VACUUM FULL ANALYZE is run every night.  There are
2000-5000 inserts on this table every day but very few updates and
deletes.  When I select count(*) from this table it is using a
sequence scan.  Is this just life or is there some way to get this to
do an index scan?

culley