Frequencies for first 10,000 rows of ordperf2 variable in nhamcsopd2003 dataset :

  surg procedure #2 - |
   ord/sched or perf? |      Freq.     Percent        Cum.
----------------------+-----------------------------------
                blank |      9,702       97.02       97.02
    ordered/scheduled |        127        1.27       98.29
            performed |        140        1.40       99.69
ordered and performed |          8        0.08       99.77
              unknown |         23        0.23      100.00
----------------------+-----------------------------------
                Total |     10,000      100.00

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