“…For the calculation of the concentration indices for the years 1995, 1996, 1997, 1998, 1999, 2000, 2001 and 2002, we have used the company directory of the National Institute (7) See Schmalensee (1977), Encaoua and Jacquemin (1980), Baumol et al (1982), Clark andy Davies (1982), Hirschey (1985), Jaumandreu and Mato (1985), Jaumandreu (1987), Scherer and Ross (1990), Schmalensee (1992), Gandoy (1988), andMartin (1993).…”