st: complicated twoway graph

[Maria Sokolova <megami2717@yahoo.com>]

Hi everyone!
Need to figure out if stata 12 can generate a twoway graph bar with two distributions both being cumulative.
Explaining on example: I have 20 periods of time for which I have 3 measures for 2 groups of companies. The measures for each group sum up to 100% per each period. 
I need a  graph akin to http://www.ats.ucla.edu/stat/stata/library/GraphExamples/code/twobar4.htm, but with cumulations on both sides for each period.
please help!

the example of the data would be:

              L1                         L2                         L2
          big     small               big    small           big     small   
q1       5         7                   8      9               12         3  
q2       6         9                  10     13              15         9  
q3       9         13                 7      9               13         8  
q4       14       16                  8      10               9        7  


Thanks in advance,
Maria

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