infile exp wks occ ind south smsa ms fem union ed blk lwage using union.txt generate year = mod((_n-1),7)+81 generate ii = int((_n-1)/7)+1 xtset ii year local it = 81 while `it'<=87{ generate d`it' = 0 quiet replace d`it' = 1 if year==`it' generate ms`it' = 0 quiet replace ms`it' = ms if year==`it' local it = `it'+1 }