Frequencies for first 10,000 rows of ordperf2 variable in nhamcsopd2004 dataset :

  surg procedure #2 - |
   ord/sched or perf? |      Freq.     Percent        Cum.
----------------------+-----------------------------------
                blank |      9,860       98.60       98.60
    ordered/scheduled |         26        0.26       98.86
            performed |         49        0.49       99.35
ordered and performed |         14        0.14       99.49
              unknown |         51        0.51      100.00
----------------------+-----------------------------------
                Total |     10,000      100.00

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