Frequencies for first 10,000 rows of ume_vac variable in natl2003 dataset :

 Vacuum U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        221        2.21        2.21
          2 |      9,750       97.50       99.71
          8 |          5        0.05       99.76
          9 |         24        0.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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