Frequencies for first 10,000 rows of metrores variable in natl1990 dataset :

 Met/Nonmet |
  county of |
  residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      6,666       66.66       66.66
          2 |      3,332       33.32       99.98
          Z |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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