In less than a decade, the growing bicycle craze created one of the largest industries in the country. In 1885, the heyday of the ordinary, there were only six cycle manufacturers in the United States, with a total annual output of 11,000 bicycles. Five years later, with the safety now available, there were 17 manufacturers, and they produced 40,000 bicycles. What type of evidence does the author use to support her argument?