Frequencies for first 10,000 rows of metrores variable in natl1972 dataset :

 Met/Nonmet |
  county of |
  residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,691       46.91       46.91
          2 |      5,308       53.08       99.99
          Z |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016