Frequencies for first 10,000 rows of nprevis variable in natl1994 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        110        1.10        1.10
          1 |         42        0.42        1.52
          2 |         59        0.59        2.11
          3 |         83        0.83        2.94
          4 |        141        1.41        4.35
          5 |        197        1.97        6.32
          6 |        302        3.02        9.34
          7 |        309        3.09       12.43
          8 |        449        4.49       16.92
          9 |        632        6.32       23.24
         10 |      1,655       16.55       39.79
         11 |        650        6.50       46.29
         12 |      1,771       17.71       64.00
         13 |        729        7.29       71.29
         14 |        899        8.99       80.28
         15 |        792        7.92       88.20
         16 |        390        3.90       92.10
         17 |        169        1.69       93.79
         18 |        139        1.39       95.18
         19 |         74        0.74       95.92
         20 |        137        1.37       97.29
         21 |         26        0.26       97.55
         22 |         31        0.31       97.86
         23 |         10        0.10       97.96
         24 |         13        0.13       98.09
         25 |         28        0.28       98.37
         26 |          7        0.07       98.44
         27 |          2        0.02       98.46
         28 |          6        0.06       98.52
         30 |          9        0.09       98.61
         31 |          2        0.02       98.63
         32 |          3        0.03       98.66
         33 |          2        0.02       98.68
         34 |          1        0.01       98.69
         35 |          2        0.02       98.71
         38 |          2        0.02       98.73
         40 |          1        0.01       98.74
         99 |        126        1.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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