Babel: Processing Tables - Ignore Some Rows

[Ian Barton <lists@wilkesley.net>]

I am using gnuplot to plot some data from a table:

#+tblname: monthly_total_mileage
|-------+----------|
| Month | Distance |
|-------+----------|
| Jan   |   272.04 |
| Feb   |   317.11 |
| Mar   |   354.27 |
| Apr   |   288.21 |
| May   |   488.35 |
| Jun   |   444.92 |
| Jul   |   497.21 |
| Aug   |   625.35 |
| Sep   |      821 |
| Oct   |    717.9 |
| Nov   |          |
| Dec   |          |
|-------+----------|
| Total |  4826.36 |
|-------+----------|


#+begin_src gnuplot :var data=monthly_total_mileage :file 
./monthly_total_mileage.png
   reset

   set boxwidth 0.5
   set xlabel 'month'
   set ylabel 'distance, km'

   plot data u 2:xticlabels(1) notitle with boxes fs solid 0.5
#+end_src

Ideally I want Babel to ignore the Totals row, so it doesn't get 
processed and plotted by gnuplot. Is there any way of doing this? I want 
to publish the data in several formats, some of which require me to 
display the total and some of which don't.

Any other workarounds gratefully accepted.

Ian.