Frequencies for first 10,000 rows of nprev12 variable in natl1983 dataset :

  Number of |
   Prenatal |
     Visits |
     Recode |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        180        1.80        1.80
          2 |        394        3.94        5.74
          3 |        514        5.14       10.88
          4 |        830        8.30       19.18
          5 |      1,144       11.44       30.62
          6 |      1,721       17.21       47.83
          7 |      2,397       23.97       71.80
          8 |      1,589       15.89       87.69
          9 |        747        7.47       95.16
         10 |        184        1.84       97.00
         11 |        230        2.30       99.30
         12 |         70        0.70      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016