Frequencies for first 10,000 rows of prescr2 variable in nhamcsopd1992 dataset :

Prescriptio |
   n status |
   code for |
 medication |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,954       19.54       19.54
          2 |        398        3.98       23.52
          3 |        326        3.26       26.78
          . |      7,322       73.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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