Exxon expects to see more and more hybrids on the world's roads, with gas-sipping models like the Toyota Prius making up half of all vehicles by 2040.

The largest publicly traded oil and gas company says in its annual energy outlook that the use of hybrids — vehicles that rely on both gas and electricity for power — and other efficiency gains will keep energy demand in check for the U.S. and other major industrialized countries for years.

Exxon Mobil Corp. predicts that energy demand will remain flat through 2040 in developed nations.

However, Exxon says that China and other developing nations will increase their thirst for oil and other petroleum based fuels. Energy demand within developing nations is expected to rise nearly 60 percent from 2010 to 2040.