Frequencies for first 10,000 rows of pt variable in nhamcsopd2008 dataset :

   physical |
    therapy |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,690       96.90       96.90
        yes |        310        3.10      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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