Frequencies for first 10,000 rows of uop_tocol variable in natl2006 dataset :

  Tocolysis |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         73        0.73        0.73
          2 |      9,793       97.93       98.66
          9 |        134        1.34      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015