pg_stat_all_tables shows all 0's

Hi,

  When I query the pg_stat_all_tables view all I get back is 0's.  How
can I tell if the statistics collector is running?  I have the  param's
set in my config file.

#
#    Access statistics collection
#
stats_start_collector = true
stats_reset_on_server_start = true
stats_command_string = false
stats_row_level = false
stats_block_level = false

thanks
michael