Frequencies for first 10,000 rows of orbit variable in pos1988 dataset :

 Orbit Code |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,903       49.03       49.03
          2 |        821        8.21       57.24
          3 |      4,275       42.75       99.99
          . |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016