Frequencies for first 10,000 rows of nprev12 variable in natl1990 dataset :

  Number of |
   Prenatal |
     Visits |
     Recode |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        189        1.89        1.89
          2 |        168        1.68        3.57
          3 |        348        3.48        7.05
          4 |        682        6.82       13.87
          5 |      1,071       10.71       24.58
          6 |      2,054       20.54       45.12
          7 |      2,550       25.50       70.62
          8 |      1,295       12.95       83.57
          9 |        957        9.57       93.14
         10 |        225        2.25       95.39
         11 |        351        3.51       98.90
         12 |        110        1.10      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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