Frequencies for first 10,000 rows of drg3ing4 variable in nhamcsed1998 dataset :

 ingredient |
code #4 for |
    drug #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,986       99.86       99.86
      54468 |          1        0.01       99.87
      54713 |          3        0.03       99.90
      55180 |          9        0.09       99.99
      56310 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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