iostat values zero'ed?

[Aaron Glenn]

Apologizes for the lame question but after a good search of the
archives, testing on the other unix boxen I have around, and finding
nothing interesting in the man page, I'm at a loss as to why the
initial values iostat output are zero'ed.
rubber# iostat -c 1000
     tty             da0              fd0            pass0             cpu
tin tout  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
  0  143  0.00   0  0.00   0.00   0  0.00   0.00   0  0.00   9  0  2  1 88
  0   77 16.00   2  0.03   0.00   0  0.00   0.00   0  0.00   0  0  1  2 97
  0   77 16.00   2  0.03   0.00   0  0.00   0.00   0  0.00   0  0  0  0 100
  0   78 16.00   2  0.03   0.00   0  0.00   0.00   0  0.00   0  0  0  1 99
  0   77 16.00   4  0.06   0.00   0  0.00   0.00   0  0.00   0  0  0  1 99
  0   77 16.00   2  0.03   0.00   0  0.00   0.00   0  0.00   0  0  1  1 98
  0   77 16.00   2  0.03   0.00   0  0.00   0.00   0  0.00   0  0  5  1 95
  0   77 16.00   2  0.03   0.00   0  0.00   0.00   0  0.00   0  0  0  1 99
^C
rubber# uname -a
DragonFly rubber.nsindus.net 1.7.0-DEVELOPMENT DragonFly
1.7.0-DEVELOPMENT #0: Sun Aug 13 03:11:51 CEST 2006
root at xxxxxxxxxxxxxxxxxxxxxx:/usr/obj/usr/src/sys/GENERIC  i386
rubber#
feel free to bust out the cluebat...

regards,
aaron.glenn