Frequencies for first 10,000 rows of prescr2 variable in nhamcsed1999 dataset :

prescriptio |
   n status |
   code for |
    drug #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,785       27.85       27.85
          2 |        717        7.17       35.02
          3 |        520        5.20       40.22
          . |      5,978       59.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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