boxplot tick locations

hi all-

i am creating a boxplot and would like to shift the x-axis tick marks 
(named 1:23) so that the ticks are in between the boxes and not centered 
in the middle of the boxes. i have searched the help files and google 
and have not found what i am looking for.

does anyone know how to do this?

thanks!

s.heck
University of Colorado, Boulder