Frequencies for first 10,000 rows of vyear variable in namcs2004 dataset :

    year of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
       2003 |        215        2.15        2.15
       2004 |      9,785       97.85      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016