Microwaves in U.S. households
In 1978, only eight percent of U.S. households had microwave ovens. As of 2006 over 80 percent have them.

Reference: http://www.powerhousetv.com/
More facts about the United States.
In 1978, only eight percent of U.S. households had microwave ovens. As of 2006 over 80 percent have them.
The size of a typical American home has increased from 1100 to 1800 square feet over the past ten years.
Natural gas provides 24 percent of all the energy used in the United States