Frequencies for first 10,000 rows of pt variable in nhamcsopd2010 dataset :

   physical |
    therapy |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,575       95.75       95.75
        yes |        425        4.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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