More and more businesses and homeowners are installing solar panels on their roofs to draw energy from the sun's rays. According to the U.S. Department of Energy, the solar cell kilowatt-hour use in the United States (in millions) is projected to be S(t) = 0.73t2 + 15.8t +2.7 (0 < t < 8) in year t, with t = 0 corresponding to 2000.
What was the number of projected solar cell kilowatt-hours used in the United States for 2001? For 2002?