Frequencies for first 10,000 rows of prescr3 variable in nhamcsed1998 dataset :

prescriptio |
   n status |
   code for |
    drug #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,283       12.83       12.83
          2 |        278        2.78       15.61
          3 |        187        1.87       17.48
          . |      8,252       82.52      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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