AWK create loop for fields

Hi everybody:
I just create awk script. This script calculate the average of a field, but i want to do it for every fields.
The original field has 40 fields of numbers like that:

38.00 51.00 10.00 -99.90 75.00 47.00 4.00 -99.90 69.00 121.00 62.00 6.00 70.00 43.00 36.00 49.00 8.00 36.00 50.00 74.00 125.00 41.00 70.00 39.00 24.00 33.00 53.00 -99.90 70.00 2.00 24.00 71.00 28.00 122.00 31.00 -99.90 40.00 39.00 28.00 94.00 06/26/2005 00:10 (this is only one row, this is field $0)

and the script is:

BEGIN{ FS=" "; sum=0; iFinal=6;}
{
(*)
{
if (NR<=iFinal)
{
sum=sum + $1;
if (NR==iFinal)
{
average=sum/6;
printf "%.4s\n", average;
}
}
else
{
iFinal=NR +5;
sum= $1;
}
}
}

I tried to do this with "for" like this:

for (j=1; j<=40; j++) # put it on (*)

But do not function correctly. Could anybody help how do it?.
Thanks in advance.

don't quite understand your code, but....
if you want to calculate the average for every field accross all the records/lines, here's some thing to start with. Notice the last two fields on every line are not considered AND also it's assumed that ALL the records/lines have the same number of fields.

{
  for(i=1; i < NF-2; i++)
    arr += $i

  _nf=i
}
END {
  for(i=1; i<=_nf; i++)
    printf("%.2f%s", arr/NR, (i!=_nf) ? OFS : "\n")
}