Frequencies for first 10,000 rows of segmentid variable in ma2012 dataset :

 Segment ID |      Freq.     Percent        Cum.
------------+-----------------------------------
          . |          6        0.06        0.06
          0 |      9,252       92.52       92.58
          1 |         84        0.84       93.42
          2 |         55        0.55       93.97
          3 |        324        3.24       97.21
          4 |        112        1.12       98.33
          5 |         91        0.91       99.24
          6 |         58        0.58       99.82
          9 |         18        0.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 14 Apr 2016