This question was asked several months ago... unfortunately, I'm unable to locate the thread. The point is, it really depends on the intent of your question. If you mean only the continental U.S., Alaska and Hawaii, I would concur with Q... however, if Daylight Savings Time is taken into consideration, then a couple more are added since Arizona and the city of Indianapolis do not observe the change. Additionally, Guam and other U.S. territorial possessions brings the total to, if I recall correctly about 11. Pendatic in the uttermost, but accurate depending on the real question...