The rear-wheel-drive C15 model gets a combined 19 mpg (16 mpg city, 23 mpg highway), and the four-wheel-drive K15 model comes in at 18 mpg combined (16 mpg city, 22 mpg combined). Those ratings are achieved by the redesigned 5.3-liter V-8 engine paired with a six-speed automatic.
The map on the right shows that lightning is not distributed evenly around the planet. About 70% of lightning occurs on land in the Tropics, where the majority of thunderstorms occur. The north and south poles and the areas over the oceans have the fewest lightning strikes.
Lightning happens when the negative charges (electrons) in the bottom of the cloud are attracted to the positive charges (protons) in the ground. The accumulation of electric charges has to be great enough to overcome the insulating properties of air.