Frequencies for first 10,000 rows of musculo variable in natlterr2000 dataset :

      Other |
musculoskel |
etal/integu |
     mental |
  anomalies |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          3        0.03        0.03
          2 |      9,988       99.88       99.91
          9 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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