Frequencies for first 10,000 rows of uop_tocol variable in natl2005 dataset :

  Tocolysis |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         97        0.97        0.97
          2 |      9,795       97.95       98.92
          9 |        108        1.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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