Suppose that the world market for calcium is perfectly competitive and that, as a first approximation, all existing producers and potential entrants are identical. Consider the following information about the price of calcium:
• Between 1990 and 1995, the market price was stable at about $2 per pound.
• In the first three months of 1996, the market price doubled, reaching a high of $4 per pound, where it remained for the rest of 1996.
• Throughout 1997 and 1998, the market price of calcium declined, eventually reaching $2 per pound by the end of 1998.
• Between 1998 and 2002, the market price was stable at about $2 per pound.
Assuming that the technology for producing calcium did not change between 1990 and 2002 and that input prices faced by calcium producers have remained constant, what explains the pattern of prices that prevailed between 1990 and 2002? Is it likely that there are more producers of calcium in 2002 than there were in 1990? Fewer? The same number? Explain your answer.