Frequencies for first 10,000 rows of tbo variable in natl2004 dataset :

Total Birth |
  Order U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,650       26.50       26.50
          2 |      2,267       22.67       49.17
          3 |      1,509       15.09       64.26
          4 |        950        9.50       73.76
          5 |        532        5.32       79.08
          6 |        293        2.93       82.01
          7 |        210        2.10       84.11
          8 |        102        1.02       85.13
          9 |         71        0.71       85.84
         10 |         35        0.35       86.19
         11 |         23        0.23       86.42
         12 |         18        0.18       86.60
         13 |         14        0.14       86.74
         14 |          8        0.08       86.82
         15 |          4        0.04       86.86
         16 |          2        0.02       86.88
         17 |          1        0.01       86.89
         99 |      1,311       13.11      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 21 Jan 2016