"Assume that the population of the U.S. increases by 1%/yr. How many BTU of energy will have to be added to the national annual energy budget this year to maintain the same per capita expenditure?" The current populations is listed as 291 million. And the current per capita energy expenditure = 58 barrels of oil. I wasn't sure what to do. I guessed and ended up with 9.7776 X 10 to the 14, BTU increase. Can anyone help me out a bit?