Frequencies for first 10,000 rows of nprevis variable in natl1995 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         93        0.93        0.93
          1 |         40        0.40        1.33
          2 |         39        0.39        1.72
          3 |         73        0.73        2.45
          4 |        108        1.08        3.53
          5 |        159        1.59        5.12
          6 |        331        3.31        8.43
          7 |        267        2.67       11.10
          8 |        479        4.79       15.89
          9 |        446        4.46       20.35
         10 |      1,550       15.50       35.85
         11 |        671        6.71       42.56
         12 |      1,672       16.72       59.28
         13 |        664        6.64       65.92
         14 |        921        9.21       75.13
         15 |      1,033       10.33       85.46
         16 |        483        4.83       90.29
         17 |        220        2.20       92.49
         18 |        219        2.19       94.68
         19 |         94        0.94       95.62
         20 |        175        1.75       97.37
         21 |         32        0.32       97.69
         22 |         33        0.33       98.02
         23 |         19        0.19       98.21
         24 |         16        0.16       98.37
         25 |         31        0.31       98.68
         26 |          9        0.09       98.77
         27 |          7        0.07       98.84
         28 |          3        0.03       98.87
         29 |          1        0.01       98.88
         30 |         10        0.10       98.98
         31 |          2        0.02       99.00
         33 |          1        0.01       99.01
         35 |          1        0.01       99.02
         40 |          2        0.02       99.04
         42 |          1        0.01       99.05
         49 |          2        0.02       99.07
         99 |         93        0.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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