1990 salary, thousands $
% change salary, 89-90
1990 firm sales, millions $
return on equity, 88-90 avg
% change roe, 88-90
return on firm's stock, 88-90
=1 if industrial firm
=1 if financial firm
=1 if consumer product firm
=1 if transport. or utilties
natural log of salary
natural log of sales