Frequencies for first 10,000 rows of prescr1 variable in nhamcsed1998 dataset :

prescriptio |
   n status |
   code for |
    drug #1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,598       45.98       45.98
          2 |      1,258       12.58       58.56
          3 |      1,003       10.03       68.59
          . |      3,141       31.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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