Frequencies for first 10,000 rows of cardmon variable in nhamcsed2007 dataset :

    cardiac |
    monitor |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,100       91.00       91.00
        yes |        900        9.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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