The U.S. Government Accountability Office said in a Dec. 19 report that the estimated volume of pharmaceutical and biotechnology sales revenues rose from $534 billion in 2006 to $775 billion in 2015, and that roughly two-thirds of companies saw an increase in profit margins over the same term. GAO said the 25 largest firms had profit margins of between 15 and 2 percent, substantially greater than the 4 to 9 percent enjoyed by the 500 largest global companies in other industries.