Frequencies for first 10,000 rows of nprev12 variable in natl1980 dataset :

  Number of |
   Prenatal |
     Visits |
     Recode |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        125        1.25        1.25
          2 |        333        3.33        4.58
          3 |        571        5.71       10.29
          4 |        925        9.25       19.54
          5 |      1,342       13.42       32.96
          6 |      1,928       19.28       52.24
          7 |      2,234       22.34       74.58
          8 |      1,483       14.83       89.41
          9 |        621        6.21       95.62
         10 |        175        1.75       97.37
         11 |        164        1.64       99.01
         12 |         99        0.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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