Thanks to Kit Baum a new package -proprcspline- is now available 
from SSC. To install type -ssc install proprcspline-. 
-proprcspline- computes a restricted cubic spline smooth of
proportions of observations in each category of a dependent/
response/explained variable given an independent/predictor/
explanatory variable, and graphs these smoothed proportions 
as a stacked area plot. For example, I have used this to 
plot how the educational distribution has changed over 
cohorts.
-- Maarten
-----------------------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://home.fsw.vu.nl/m.buis/
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