Frequencies for first 10,000 rows of uop_tocol variable in natl2007 dataset :

  Tocolysis |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         58        0.58        0.58
          2 |      9,322       93.22       93.80
          9 |        620        6.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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