America is the land of the automobile. This country has only 6 percent of the world's population but 46 percent of the world's cars. Right now, there are 97 million privately owned cars consuming 75 billion gallons of gasoline and traveling an estimated 1,000 billion miles, a year. The figures also affirm something we know every time we refill our gasoline tank. The automobile is a very thirsty piece of technology. Of the total petroleum supply in the United States, 30 percent goes to quench that thirst. Every year for each passenger car, about 800 gallons of gasoline are consumed. Other aspects of our commitment to the automobile also bear mentioning here, it takes a great deal of energy to manufacture one automobile—about 150 million BTUs of energy. This is equivalent to 1,200 gallons of gasoline, enough to run a car for about 16,000 miles. We expend energy in the process of shipping cars from factories to showrooms, displaying them for sale hand making replacement parts for repairs. One out of six jobs in the nation is associated with the automobile business. About two gallons of gasoline are consumed in the process of making every ten gallons that are pumped into an automobile's gas tank. Building highways and parking lots has used up much of our land. It has been estimated that we have paved over 21,000 square miles of this country's surface, most of it to accommodate the automobile. The automobile is also the largest contributor to our nation's air pollution problem and a very serious one because most of its pollutants are emitted in our large metropolitan areas. Aside from the great impact that would occur if everyone seriously practised conservation, one should stop and think about his own casual use of the automobile. There are numerous situations where better planning and awareness could really make a difference in energy savings and dollars. Because the automobile uses the largest percentage of energy in an average American family's energy budget and almost half of the dollars, the impetus for savings is tremendous. According to the author, what do most people realize?______