WASHINGTON - America’s population is on track to hit 300 million on Tuesday morning, and it’s causing a stir among environmentalists.
People in the United States are consuming more than ever — more food, more energy, more natural resources. Open spaces are shrinking and traffic in many areas is dreadful.
But some experts argue that population growth only partly explains America’s growing consumption. Just as important, they say, is where people live, what they drive and how far they travel to work.11 million to 12 million illegal immigrants in the U.S. are included in official population estimates, though many demographers believe they are undercounted.Fifty percent increase in 39 yearsThe population reached its last milestone, 200 million, in 1967. That translates into a 50 percent increase in 39 years.
During the same period, the number of households nearly doubled, the number motor vehicles more than doubled and the miles driven in those vehicles nearly tripled.

The U.S. is the third largest country in the world, behind China and India. The U.S. is the fastest growing of the industrialized nations, adding about 2.8 million people a year, or just under 1 percent. India is growing faster but the United Nations considers it to be a less developed country.
About 40 percent of U.S. population growth comes from immigration, both legal and illegal, according to the Census Bureau. The rest comes from births outnumbering deaths.