Frequencies for first 10,000 rows of copd variable in nhamcsopd1995 dataset :

       does |
    patient |
have - copd |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,760       97.60       97.60
          1 |        240        2.40      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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