In the 1960s, firms in the computer industry were able to earn extremely large profit margins, some as high as 50 to 60 percent. Margins decreased to 20 to 40 percent in the 1970s and to 10 to 20 percent in the 1980s. We conclude that: Group of answer choices The industry's Herfindahl-Hirshman index (HHI) likely increased in the two decades. Lower profit margins were largely due to the mismanagement of computer firms. The market power of firms increased in the two decades. The industry evolved from oligopolistic to a more competitive industry in the two decades. Lower profit margins were due to the government's regulation to protect consumers