Over the past decade, the number of companies that sell seeds for commodity crops like corn and soybeans has dramatically decreased. Farmers are dependent on a smaller number of firms for seeds, and the prices have risen sharply as the market has become more concentrated. The seed industry, which once relied on universities for most research and development, is now dominated by a few major chemical and pharmaceutical giants that patent specific traits in seeds and charge fees to farmers who use their patented seeds. Since 1990, the largest seed companies (many of them biotechnology firms) acquired many small- and medium-sized seed companies, reducing competition in conventional and biotech seeds. Between 1996 and 2007, Monsanto, the largest supplier of genetically modified seed traits, acquired more than a dozen smaller companies, and now controls 60 percent of corn and 62.5 percent of soybean seeds and seed trait licenses in the United States.