Frequencies for first 10,000 rows of contsub1 variable in nhamcsopd2002 dataset :

 controlled |
  substance |
   code for |
 medication |
         #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        138        1.38        1.38
          3 |         72        0.72        2.10
          4 |        114        1.14        3.24
          5 |         11        0.11        3.35
          6 |      5,109       51.09       54.44
          7 |        176        1.76       56.20
          . |      4,380       43.80      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016