COST     I      II     III      IV       V      VI
  1   3.154   3.859  19.035  35.229  33.154  73.050
  2   4.271   5.535  26.041  51.111  40.044  98.846
  3   4.584   8.127  32.444  61.045  43.125  138.88
  4   5.849  10.966  41.180  77.885  57.727  191.56
/*
Data Description:
  Panel data  of total generation cost (including fuel, labor,
  and capital costs) in millions of dollars for six firms
  (I, II, III, IV, V, IV) in four time periods (1, 2, 3, 4)
Data Source:
  W. Greene, "Simutaneous Estimation of Factor Subsititution, 
  Economies of Scale, and Non-Neutral Technical Change," in 
  A. Dogramaci, ed. Econometric Analyses of Productivity,
  Kluwer-Nijoff, Boston, 1983. Also see W. Greene [1997], 
  Chap. 14, p. 614.
*/