Frequencies for first 10,000 rows of nprevis variable in natlterr1995 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        164        1.64        1.64
          1 |         24        0.24        1.88
          2 |         77        0.77        2.65
          3 |        171        1.71        4.36
          4 |        248        2.48        6.84
          5 |        359        3.59       10.43
          6 |        618        6.18       16.61
          7 |        660        6.60       23.21
          8 |        932        9.32       32.53
          9 |        746        7.46       39.99
         10 |      1,859       18.59       58.58
         11 |        624        6.24       64.82
         12 |      1,397       13.97       78.79
         13 |        451        4.51       83.30
         14 |        570        5.70       89.00
         15 |        494        4.94       93.94
         16 |        226        2.26       96.20
         17 |         77        0.77       96.97
         18 |        123        1.23       98.20
         19 |         35        0.35       98.55
         20 |         69        0.69       99.24
         21 |         15        0.15       99.39
         22 |         13        0.13       99.52
         23 |          4        0.04       99.56
         24 |          3        0.03       99.59
         25 |         12        0.12       99.71
         26 |          3        0.03       99.74
         28 |          1        0.01       99.75
         29 |          1        0.01       99.76
         31 |          2        0.02       99.78
         34 |          1        0.01       99.79
         36 |          1        0.01       99.80
         37 |          1        0.01       99.81
         38 |          1        0.01       99.82
         39 |          1        0.01       99.83
         40 |          3        0.03       99.86
         99 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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