Performance impact of setting PostgreSQL to log all statements

Question

PostgreSQL 9.2.2 on Windows 7 64-bit.

The setting log_statement in the postgresql.conf file specifies what statements to log (none, DDL, data-modifying, or all). To what extent does setting log_statement = 'all' degrade performance? I've read that this significantly reduces performance, but these claims come from older articles, so just how much of a performance loss should I expect relative to log_statement = 'none'?