Can you help me determine if the following passage is an argument? This is for my symbolic logic class and we use Hurley's Concise Introduction to Logic. The passage:

Although it is customary to think of human population as increasing continuously without declines or fluctuations, population growth has not been a steady march. For example, great declines occurred during the time of the Black Death, during the fourteenth century. Entire towns were abandoned, production of food declined, and in England, one-third of the population died within a single decade.

My answer is that it is an argument by example, but my friends say it is an example of a nonargument illustration.