Frequencies for first 10,000 rows of precip variable in linkco1991us_num dataset :

Precipitous |
  labor (<3 |
     hours) |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        236        2.36        2.36
          2 |      9,557       95.57       97.93
          9 |        207        2.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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