The knowledge and information revolution began at the turn of the twentieth century and has gradually accelerated. By 1976 the number of white-collar workers employed in offices surpassed the number of farm workers, service workers, and blue-collar workers employed in manufacturing. Today, most people no longer work on farms or in factories but instead are found in sales, education, healthcare, banks, insurance firms, and law firms; they also provide business services like copying, computer programming, or making deliveries. These jobs primarily involve working with, distributing, or creating new knowledge and information. In fact, knowledge and information work now account for a significant 60 percent of the American gross national product and nearly 55 percent of the labor force.